Journal articles on the topic 'Rhizosphere'
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Khan, Abdul Latif, Sajjad Asaf, Raeid M. M. Abed, Yen Ning Chai, Ahmed N. Al-Rawahi, Tapan Kumar Mohanta, Ahmed Al-Rawahi, Daniel P. Schachtman, and Ahmed Al-Harrasi. "Rhizosphere Microbiome of Arid Land Medicinal Plants and Extra Cellular Enzymes Contribute to Their Abundance." Microorganisms 8, no. 2 (February 5, 2020): 213. http://dx.doi.org/10.3390/microorganisms8020213.
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Revealing the unexplored rhizosphere microbiome of plants in arid environments can help in understanding their interactions between microbial communities and plants during harsh growth conditions. Here, we report the first investigation of rhizospheric fungal and bacterial communities of Adenium obesum, Aloe dhufarensis and Cleome austroarabica using next-generation sequencing approaches. A. obesum and A. dhufarensis grows in dry tropical and C. austroarabica in arid conditions of Arabian Peninsula. The results indicated the presence of 121 fungal and 3662 bacterial operational taxonomic units (OTUs) whilst microbial diversity was significantly high in the rhizosphere of A. obesum and A. dhufarensis and low in C. austroarabica. Among fungal phyla, Ascomycota and Basidiomycota were abundantly associated within rhizospheres of all three plants. However, Mucoromycota was only present in the rhizospheres of A. obesum and A. dhufarensis, suggesting a variation in fungal niche on the basis of host and soil types. In case of bacterial communities, Actinobacteria, Proteobacteria, Bacteroidetes, Planctomycetes, Acidobacteria, and Verrucomicrobia were predominant microbial phyla. These results demonstrated varying abundances of microbial structure across different hosts and locations in arid environments. Rhizosphere’s extracellular enzymes analysis revealed varying quantities, where, glucosidase, cellulase, esterase, and 1-aminocyclopropane-1-carboxylate deaminase were significantly higher in the rhizosphere of A. dhufarensis, while phosphatase and indole-acetic acid were highest in the rhizosphere of A. obesum. In conclusion, current findings usher for the first time the core microbial communities in the rhizospheric regions of three arid plants that vary greatly with location, host and soil conditions, and suggest the presence of extracellular enzymes could help in maintaining plant growth during the harsh environmental conditions.
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Ahmad, Maqshoof, Zafar Iqbal, Bushra, Azhar Hussain, Muhammad Abdullah, Abed Alataway, Ahmed Z. Dewidar, and Mohamed A. Mattar. "Seasonal Changes Modulate the Rhizosphere of Desert Plant Species." Agronomy 13, no. 1 (December 23, 2022): 57. http://dx.doi.org/10.3390/agronomy13010057.
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Arid and semi-arid ecosystems are categorized as having degraded soils due to the limited availability of water and nutrients. The perennial shrubs in these regions have developed different ecological and physiological adaptations to cope with harsh conditions. The plant species vary in the chemical profile of their root exudates, which can induce variability in the microbial community in the rhizosphere. The present research has been conducted (i) to investigate the variation in composition, diversity, and structure of rhizosphere’s bacterial community of desert plants; (ii) to identify plant-specific effects on the rhizosphere microbial community structure; and (iii) to determine the influence of soil moisture on the rhizosphere’s microbial community and soil biological properties under stressful conditions. Ten desert plant species from the Cholistan desert were selected as test specimens. Bacterial communities from the rhizosphere of 10 plants of each species were explored. Soil samples were collected during monsoon (June–August) and dry months (March–May). Microbial community structure analyses were carried out through 16S rRNA sequencing by targeting V3 and V4 regions. Among tested plant species, the rhizosphere of Leptadenia pyrotechnica (S6 vs. S16), Aerva javanica (Burm. f.) Juss. ex Schult (S9 vs. S19), and Vachellia jacquemontii (Benth.) (S10 vs. S20) had greater microbial diversity in both seasons. Higher levels of microbial communities were found during monsoon season. Furthermore, Gammaproteobacteria were abundant in the rhizospheres of all studied plants during the monsoon season. In contrast, the rhizosphere was abundant with unidentified_Actinobacteria during the dry season. The rhizospheric soil was further analyzed for biological properties. The maximum microbial biomass carbon (165 mg kg–1) and microbial biomass nitrogen (6.7 mg kg–1) were found in the rhizosphere of Vachellia jacquemontii (Benth.) Benth during monsoon season. However, a minimum of microbial biomass carbon (119 mg kg–1) and microbial biomass nitrogen (4.2 mg kg–1) were found in the rhizosphere of Cleome pallida Kotschy during dry seasons. The diversified microbial community structure and biological properties enable desert plants to cope with adverse climate conditions.
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Jamiołkowska, Agnieszka, Barbara Skwaryło-Bednarz, Elżbieta Patkowska, Halina Buczkowska, Anna Gałązka, Jarosław Grządziel, and Marek Kopacki. "Effect of Mycorrhizal Inoculation and Irrigation on Biological Properties of Sweet Pepper Rhizosphere in Organic Field Cultivation." Agronomy 10, no. 11 (October 31, 2020): 1693. http://dx.doi.org/10.3390/agronomy10111693.
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The aim of the study was to evaluate the influence of mycorrhizal fungi (MF) and irrigation on biological properties of sweet pepper rhizosphere in organic field cultivation. For this purpose, MF were applied to plants in the form of commercial mycorrhizal inoculum (Rhizophagus aggregatus, R. intraradices, Claroideoglomus etunicatum, Endogone mosseae, Funneliformis caledonium, and Gigaspora margarita) and irrigation according to the combinations: mycorrhized plants (PM), mycorrhized and irrigated plants (PMI), and irrigated plants (PI). Plants without MF and irrigation served as the absolute control (P). The study used classic and molecular techniques, assessing catalase activity, biodiversity of soil microorganisms (soil DNA analysis), and the Community-Level Physiological Profiles (CLPP) analysis using Biolog EcoPlates. The highest catalase activity was recorded in the control and mycorrhized soil sample. The highest total number of bacteria was noted in the rhizosphere of control plants (P) and irrigated plants, while the lowest number in the rhizosphere of mycorrhized and irrigated plants. Plant irrigation contributed to the increase in the total number of fungi in the rhizosphere. The rhizospheric soil of PM and PMI were characterized by the highest utilization of amines, amides, and amino acids, whereas the lowest level of utilization was detected in the P and PI rhizospheres. The highest biodiversity and metabolic activity were observed in the rhizospheres from the PMI and PM samples, whereas lower catabolic activity were recorded in the P and PI rhizospheres. The mycorrhization of crops improved the biological properties of the rhizosphere, especially under conditions of drought stress.
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Sun, Yan, Ziyue Huang, Siyu Chen, Da Yang, Xinru Lin, Wenjun Liu, and Shangdong Yang. "Higher-Quality Pumpkin Cultivars Need to Recruit More Abundant Soil Microbes in Rhizospheres." Microorganisms 10, no. 11 (November 9, 2022): 2219. http://dx.doi.org/10.3390/microorganisms10112219.
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Two different qualities of pumpkin, cultivars G1519 and G1511, were grown in the same environment under identical management. However, their qualities, such as the contents of total soluble solids, starch, protein, and vitamin C, were significantly different. Do rhizospheric microbes contribute to pumpkin quality? To answer this question, this study investigated the soil microbial compositions in the rhizospheres of different quality pumpkin cultivars to determine the differences in these soil microbial compositions and thus determine how soil microbes may affect pumpkin quality. Firstly, a randomized complete block design with two pumpkin cultivars and three replications was performed in this study. The soil microbial compositions and structures in the rhizospheres of the two pumpkin cultivars were analyzed using a high-throughput sequencing technique. In comparison with the low-quality pumpkin cultivar (G1519), higher microbial diversity and richness could be found in the rhizospheres of the high-quality pumpkin cultivar (G1511). The results showed that there were significant differences in the soil bacterial and fungal community compositions in the rhizospheres of the high- and low-quality pumpkin cultivars. Although the compositions and proportions of microorganisms were similar in the rhizospheres of the two pumpkin cultivars, the proportions of Basidiomycota and Micropsalliota in the G1519 rhizosphere were much higher than those in the G1511 rhizosphere. Furthermore, the fungal phylum and genus Rozellomycota and Unclassified_p__Rozellomycota were unique in the rhizosphere of the high-quality pumpkin cultivar (G1511). All the above results indicate that soil microbes were enriched differentially in the rhizospheres of the low- and high-quality pumpkin cultivars. In other words, more abundant soil microbes were recruited in the rhizosphere of the high-quality pumpkin cultivar as compared to that of the low-quality cultivar. Rozellomycota and Unclassified_p__Rozellomycota may be functional microorganisms relating to pumpkin quality.
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Shen, Qingqing, Junyu Yang, Daifa Su, Zhiying Li, Wei Xiao, Yongxia Wang, and Xiaolong Cui. "Comparative Analysis of Fungal Diversity in Rhizospheric Soil from Wild and Reintroduced Magnolia sinica Estimated via High-Throughput Sequencing." Plants 9, no. 5 (May 8, 2020): 600. http://dx.doi.org/10.3390/plants9050600.
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Magnolia sinica is a critically endangered species and considered a “plant species with extremely small populations” (PSESP). It is an endemic species in southeastern Yunnan Province, China, with reproductive barriers. Rhizosphere fungi play a crucial role in plant growth and health. However, the composition, diversity, and function of fungal communities in wild and reintroduced M. sinica rhizospheres remain unknown. In this study, Illumina sequencing of the internal transcribed spacer 2 (ITS2) region was used to analyze rhizospheric soil samples from wild and reintroduced M. sinica. Thirteen phyla, 45 classes, 105 orders, 232 families, and 433 genera of fungi were detected. Basidiomycota and Ascomycota were dominant across all samples. The fungal community composition was similar between the wild and reintroduced rhizospheres, but the fungal taxa relative abundances differed. The fungal community richness was higher in the reintroduced rhizosphere than in the wild rhizosphere, but the diversity showed the opposite pattern. Soil nutrients and leaf litter significantly affected the fungal community composition and functional diversity. Here, the composition, structure, diversity, and ecological functions of the fungal communities in the rhizospheres of wild and reintroduced M. sinica were elucidated for the first time, laying a foundation for future research and endangered species protection.
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Dong, J., W. H. Mao, G. P. Zhang, F. B. Wu, and Y. Cai. "Root excretion and plant tolerance to cadmium toxicity - a review." Plant, Soil and Environment 53, No. 5 (January 7, 2008): 193–200. http://dx.doi.org/10.17221/2205-pse.
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Significant quantities of Cd have been added to soils globally due to various anthropogenic activities, posing a serious threat to safe food production and human health. Rhizosphere, as an important interface of soil and plant, plays a significant role in the agro-environmental system. This article presents a review of relationship between root excretion and microorganisms and plant resistance to Cd toxicity and possible mechanisms. Root exudates markedly altered in species and quantity under Cd stress. Root exudates can affect Cd absorption by plants through changing the physical and chemical characteristics of rhizospheres. The influence of root exudates on Cd bioavailability and toxicity may include modifying the rhizosphere pH and Eh, chelating/complexing and depositing with Cd ions, and altering the community construction, the numbers and activities of rhizospheric microbes. In this paper, the methods to reduce the transfer of Cd in soil-plant system by adjusting rhizosphere environment are discussed, and some aspects are also proposed that should be emphasized in the future research work.
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Allaouia, Ahmed Said Allaoui, Sailine Raissa, Said Hassane Fahimat, Soudjay Asnat, An-icha Mohamed, Nemati Mohamed Abdou, Soifiata Said Ismail, et al. "Bacterial population of Rhizospheres and non-Rhizospheres of the mangrove species Rhizophora mucronata from 0 to 10 cm deep." International Journal of Advanced Engineering Research and Science 9, no. 8 (2022): 079–89. http://dx.doi.org/10.22161/ijaers.98.11.
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The interaction of plants and microorganisms in the rhizospheres and non-rhizospheres of plants is well studied and mastered in the terrestrial environment. In general, given the rhizosphere effect exclusively defining the effectiveness of root exudates to promote multiplication, development and microbial growth in the rhizosphere zones, studies unanimously tend to report that the microbial biomass is rather high in the rhizosphere than in the non-rhizosphere. However, the trend may change in the marine environment. This study was conducted in both the rhizosphere and non-rhizosphere of the mangrove species Rhizophora mucronata at different depths ranging from 0-10 cm, to assess the bacterial community in the rhizosphere and non-rhizosphere and to also address the profile of bacterial community changes. The result showed no difference regarding the bacterial abundance in the rhizosphere and in the non-rhizosphere. However, the abundance of bacteria at 0-5 cm depth was significantly higher in rhizosphere and non-rhizosphere. This could be attributed to the large amount of nutrients available in the surface layer. The unequal distribution of nutrients in the rhizosphere and non-rhizosphere of the mangrove species Rhizophora mucronata could be the consequences of mineralization, immobilization of nutrients in the soil and especially root exudation. The general results of this study can be summarized by showing that if the abundance of bacteria in the rhizosphere zones of terrestrial plants is often high, the trend may be different in aquatic plants, more particularly mangroves, which constitute a separate ecosystem.
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Thuy, Phan Thi, Wei-Ching Chung, and Li-Sen Young. "Host Genotype and Edaphic Factors Cumulatively Influence the Occurrence of Siderophore-producing Bacteria Associated with Rice (Oryza sativa L.)." Vietnam Journal of Agricultural Sciences 5, no. 1 (March 30, 2022): 1313–25. http://dx.doi.org/10.31817/vjas.2022.5.1.01.
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Seed-borne rice endophytes are capable of disseminating into host plant tissues as well as to their rhizosphere. Here, we investigated the occurrence of siderophore-producing bacteria (SPB) in the seed endospheres of two distinct rice (Oryza sativa L.) cultivars, TK8 (ssp. japonica) and TCN1 (ssp. indica), and their dissemination into the rhizospheres through culture-dependent methods. Their patterns of occurrence in the rhizospheres as well as in the root and shoot tissues of 30 day-old cultivars grown in three different kinds of soils were tested. The significance of SPB on Fe sequestration of TCN1 was studied using Enterobacter sp. LS-756. TK8 seeds were found to be not only abundant in endopsheric SPB (> 10-fold), but also exhibited enhanced SPB dissemination into the rhizosphere (1.3-fold) as compared to TCN1. The proportion of endophytic SPB was consistently higher in roots than in shoots, and it was found to decline with decreasing soil pH. A similar declining trend was further evident through the analysis of SPB composition in the rhizospheric and bulk soils. LS-756-inoculated TCN1 seedlings under low availability of Fe showed 32%, 178%, and 368% increases in Fe, chlorophyll, and chlorophyll b contents as compared to the uninoculated controls. Thus, the occurrence of seed-borne endophytic SPB and their dissemination into the rhizosphere vary significantly according to the rice genotype. Higher co-occurrence of SPB in the rhizosphere and internal root tissues of rice plants grown under Fe-limited conditions and the enhanced Fe uptake due to SPB inoculation substantiated their potential involvement in Fe sequestration.
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Applebaum, Itaii, Mareeswaran Jeyaraman, Chen Sherman, Tirza Doniger, and Yosef Steinberger. "Structure and Function of the Soil Rhizosphere Fungal Communities in Medicinal Plants—A Preliminary Study." Agriculture 12, no. 2 (January 21, 2022): 152. http://dx.doi.org/10.3390/agriculture12020152.
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Plants regulate their rhizosphere microbiome, which partly comprises the fungal community. We conducted a study in order to determine the effect that five medicinal plant species (Origanum syriacum, Salvia fruticosa, Teucrium capitatum, Myrtus communis and Pistacia lentiscus) have on the fungal community in their rhizosphere. We measured abiotic parameters and used sequencing to determine the structure of the rhizosphere fungal community, both taxonomically, as phyla and genera, and functionally, as trophic modes. Our data shows that the rhizosphere fungal communities were significantly different, both taxonomically and functionally. The rhizosphere of M. communis had a significant relative abundance of saprotrophs and a lower relative abundance of symbiotrophs than the control soil and the rhizosphere of T. capitatum. The relative abundance of the genus Aureobasidium was significantly higher in the rhizosphere of P. lentiscus than in the control and for all other rhizospheres, but that of S. fruiticosa. The relative abundance of genus Alternaria was lower in the rhizospheres of S. fruticosa and M. communis than in the control soil. Our results highlight the potential use of these plants in agroforestry, as a means to influence the soil fungi population.
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Toberman, Hannah, Chengrong Chen, and Zhihong Xu. "Rhizosphere effects on soil nutrient dynamics and microbial activity in an Australian tropical lowland rainforest." Soil Research 49, no. 7 (2011): 652. http://dx.doi.org/10.1071/sr11202.
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Via vast exchanges of energy, water, carbon, and nutrients, tropical forests are a major driving force in the regulation of Earth’s biogeochemical, hydrological, and climatic cycles. Given the critical role of rhizosphere processes in nutrient cycling, it is likely that rhizosphere processes in tropical rainforests form a major component of the biome’s interactions with global cycles. Little is known, however, about rhizospheric processes in rainforest soils. In order to investigate the influence of rhizosphere processes upon rainforest nutrient cycling, we compared the nutrient status and microbial activity of rhizospheric soil from Australian lowland tropical rainforest with that of the surrounding bulk soil. We found a marked difference in the biological and chemical nature of the rhizosphere and bulk soils. Total carbon, microbial biomass carbon, total nitrogen, soluble nitrogen, and a suite of trace element concentrations, alongside microbial respiration and the rate and diversity of carbon substrate use, were all significantly higher in the rhizosphere soil than the bulk soil. Rhizosphere soil δ15N was significantly lower than that of the bulk soil. Ratios of carbon, nitrogen, phosphorus, and sulfur differed significantly between the rhizosphere and bulk soil. These clear differences suggest that rhizosphere processes strongly influence nutrient cycling in lowland tropical rainforest, and are likely to play an important role in its interaction with global cycles. This role may be under-represented with composite sampling of rhizosphere and bulk soil. Further research is required regarding the mechanisms of rainforest rhizospheric processes and their relationship with ecosystem productivity, stability, and environmental change.
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Yudiawati, Effi. "Virulence of the Entomopathogenic Fungi Metarhizium spp. From Various Rhizosphere Against Pest Walang Sangit (Leptocorisa acuta thunb.)." Baselang 1, no. 2 (October 30, 2021): 129–38. http://dx.doi.org/10.36355/bsl.v1i2.79.
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Virulence of the Entomopathogenic Fungi Metarhizium spp. from Various Rhizospheres Against the Pest Walang Sangit (Leptocorisa acuta Thunb.). Metarhizium spp. is a type of entomopathogenic fungus that can be used to control Leptocorisa acuta. The purpose of this study was to obtain isolates of the fungus Metahrizium spp. which is virulent from various rhizospheres against L. acuta. The results of this study are expected to produce bioinsecticides with active ingredients from the entomopathogenic fungus Metahrizium spp. which are effective for controlling L. acuta pests in rice plants. Entomopathogenic fungal isolates Metarhizium spp. The samples used came from various plant rhizospheres in different regions, namely Met1a (Metarhizium spp. from the leek rhizosphere, Tanah Datar area), Met3b (Metarhizium spp. from the leek rhizosphere, Pua Agam River area), MetcTd (Metarhizium spp. from red chili rhizosphere, Tanah Datar area), Met2d (Metarhizium spp. from leek rhizosphere, Padang Lua Agam area), and MetKtBs (Metarhizium spp. from peanut rhizosphere, Batusangkar area). The results showed that some isolates of the entomopathogenic fungus Metarhizium spp. had a very significant effect on the mortality of L. acuta nymphs, L. acuta imago formed and duration of death of L. acuta. Treatment C (Met3b: Metarhizium spp. from leek rhizosphere, Pua Agam River area) was the best treatment among other treatments, with the mortality of 3 instar L. acuta nymphs of 100%, the number of imago formed 0% and the duration of death of 3 instar L. acuta nymphs with an average time of 4.50 days.
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Hu, Zhilong, and Wenhua Xiang. "Inconsistent Responses of Rhizosphere Microbial Community Structure and Extracellular Enzyme Activity to Short-Term Nitrogen and Phosphorus Additions in Chinese Fir (Cunninghamia lanceolata) Plantations." Forests 14, no. 8 (July 27, 2023): 1532. http://dx.doi.org/10.3390/f14081532.
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Rhizosphere is a hot zone formed by root–microbial interaction, and microbial activities in this zone differ from those in bulk soil. Nitrogen (N) and phosphorus (P) inputs are able to change forest soil nutrient availability, affecting microbial communities and extracellular enzyme secretion. However, the impact of N and P additions on the structure and functions of rhizosphere microbial community in Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantations are not yet clear. To reveal the impact of short-term N and P inputs on microbial community structure and functions in rhizosphere soil, soil physicochemical properties, phospholipid fatty acids, and seven hydrolytic enzyme activities were measured in Chinese fir rhizosphere soil after one year of nutrient addition. N addition reduced the rhizosphere’s pH and increased ammonium N, but the rhizosphere’s available N (AN) initially wentdown and then up along the P-addition gradient. The rhizosphere fungi:bacteria ratio showed a decline after N addition, while a concave peak change occurred as rhizosphere AN under P addition. Moreover, rhizosphere extracellular enzyme activities and microbial C limitation climbed markedly with N addition rates, while this also showed an obviously unimodal pattern along the P-addition gradient. P addition did not alleviate rhizosphere microbial P limitation. Our findings suggest inconsistent responses of rhizosphere microorganisms of Chinese fir soil to N and P additions. Rhizosphere N availability can regulate microbial community structure and extracellular enzymes by influencing microbial C limitation. The study provides more knowledge on microbial activities in rhizosphere soil of subtropical forests under global changes.
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Hou, Dandi, Zhi Lin, Runze Wang, Jun Ge, Shuai Wei, Ruohan Xie, Haixin Wang, et al. "Cadmium Exposure-Sedum alfrediiPlanting Interactions Shape the Bacterial Community in the Hyperaccumulator Plant Rhizosphere." Applied and Environmental Microbiology 84, no. 12 (April 13, 2018): e02797-17. http://dx.doi.org/10.1128/aem.02797-17.
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ABSTRACTRhizospheric bacteria play important roles in plant tolerance and activation of heavy metals. Understanding the bacterial rhizobiome of hyperaccumulators may contribute to the development of optimized phytoextraction for metal-polluted soils. We used 16S rRNA gene amplicon sequencing to investigate the rhizospheric bacterial communities of the cadmium (Cd) hyperaccumulating ecotype (HE)Sedum alfrediiin comparison to its nonhyperaccumulating ecotype (NHE). Both planting of two ecotypes ofS. alfrediiand elevated Cd levels significantly decreased bacterial alpha-diversity and altered bacterial community structure in soils. The HE rhizosphere harbored a unique bacterial community differing from those in its bulk soil and NHE counterparts. Several key taxa fromActinobacteria,Bacteroidetes, and TM7 were especially abundant in HE rhizospheres under high Cd stress. The actinobacterial genusStreptomyceswas responsible for the majority of the divergence of bacterial community composition between the HE rhizosphere and other soil samples. In the HE rhizosphere, the abundance ofStreptomyceswas 3.31- to 16.45-fold higher than that in other samples under high Cd stress. These results suggested that both the presence of the hyperaccumulatorS. alfrediiand Cd exposure select for a specialized rhizosphere bacterial community during phytoextraction of Cd-contaminated soils and that key taxa, such as the species affiliated with the genusStreptomyces, may play an important role in metal hyperaccumulation.IMPORTANCESedum alfrediiis a well-known Cd hyperaccumulator native to China. Its potential for extracting Cd relies not only on its powerful uptake, translocation, and tolerance for Cd but also on processes underground (especially rhizosphere microbes) that facilitate root uptake and tolerance of the metal. In this study, a high-throughput sequencing approach was applied to gain insight into the soil-plant-microbe interactions that may influence Cd accumulation in the hyperaccumulatorS. alfredii. Here, we report the investigation of rhizosphere bacterial communities ofS. alfrediiin phytoremediation of different levels of Cd contamination in soils. Moreover, some key taxa in its rhizosphere identified in the study, such as the species affiliated with genusStreptomyces, may shed new light on the involvement of bacteria in phytoextraction of contaminated soils and provide new materials for phytoremediation optimization.
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Piętka, Danuta, and Elżbieta Patkowska. "Effect of root exudates of various plants on composition of bacteria and fungi communities with special regard to pathogenic soil-borne fungi." Acta Agrobotanica 54, no. 1 (2013): 95–104. http://dx.doi.org/10.5586/aa.2001.009.
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The purpose of the studies conducted in the years 1996 - 1998 was to determine the composition of bacteria and fungi populations in the rhizosphere of winter wheat, spring wheat, soybean and potato, and in non-rhizosphere soil. Besides, the effect of root exudates of these plants on the formation of pathogenic fungi communities was established. The microbiological analysis showed that the greatest tolal number of bacteria was found in the rhizospheres of potato and soybean, and the lowest number in non-rhizosphere soil. The smallest total number of fungi was found in the rhizosphere of winter wheat, and the largest in the rhizosphere of soybean. Pathogenic fungi dominated in the rhizospheres of soybean and potato, while non-rhizosphere soil was the poorest in these microorganisms. Among the pathogenic fungi, <i>Fusarium oxysporum, F.culmorum</i> and <i>F.solani</i> were most frequently isolated. Soybean roots exudated the greatest amount of aminoacids, and acidic aminoacids, which have a positive effect on the development of phytopathogens, dominated in their content. On the other hand, the best quantitative and qualitative composition of aminoacids was found out in the root exudates of winter wheat, since they conlained big amounts of alkaline and aromatic aminoacids.
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Watt, M., J. A. Kirkegaard, and J. B. Passioura. "Rhizosphere biology and crop productivity—a review." Soil Research 44, no. 4 (2006): 299. http://dx.doi.org/10.1071/sr05142.
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There is great potential to use the wide genotypic and agronomically induced diversity of root systems and their exuded chemicals to influence rhizosphere biology to benefit crop production. Progress in the areas of pathogens and symbionts in this regard is clear. Further progress, especially related to interactions with non-pathogenic organisms, will rely on an appreciation of the properties of rhizospheres in the field: the spatial and temporal boundaries of these rhizospheres, and the effects of structural, chemical, and physical soil heterogeneity in which the roots and associated microorganisms exist and function. We consider the rhizosphere environment within Australian cropping systems in relation to the likely success of biological interventions, and provide 3 case studies that highlight the need to characterise the rhizosphere and the microbial interactions therein to capture agronomic benefits. New techniques are available that allow direct visualisation and quantification of rhizosphere processes in field conditions. These will no doubt help develop better genetic and agronomic approaches. Future success, as with those in the past, will rely on integrating interventions related to rhizosphere biology with other management constraints of specific farming systems.
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Widodo, Tirto Wahyu, Ilham Muhklisin, Setyo Andi Nugroho, Rudi Wardana, and Umi Safitri Alifia Ummah. "Growth and yield of maize applicated by Rizhobium spp. from legume and non-legume rhizosphere." Journal of Agriculture and Applied Biology 4, no. 2 (December 5, 2023): 151–60. http://dx.doi.org/10.11594/jaab.04.02.05.
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Rhizobium spp can affect plant growth in non-legume crops directly by synthesis of phytostimulator and solubilization of inorganic phosphate. However, the ability of Rhizobium spp from legume and non-legume rhizosphere to trigger the growth of non-legume crops is different. This research aims to analyze the ability of Rhizobium spp isolates to produce IAA hormones and phosphate solvent and determine the response of maize with the application of Rhizobum spp from the legume and non-legume rhizosphere. This study was carried out in two stages, where the first stage at Bioscience Laboratory Politeknik Negeri Jember, while the second stage at Kaliurang field, Jember, Indonesia (altitude 146 m asl, temperature 21°C - 34°C, and soil type was incepstisol) from September 2022 to January 2023. The field experiment was arranged in a complete randomized design (crd) with the application of Rhizobium spp isolates from various rhizosphere as a treatment consisting of without Rhizobium spp (control), maize-rhizosphere isolate, rice-rhizosphere isolate, soybean-rhizosphere isolate, edamame-rhizosphere isolate, and peanut-rhizosphere isolate. Every treatment was replicated four times. The results showed that Rhizobium spp isolates from legume and non-legume rhizospheres can synthesize indole acetic acid and solubilize phosphate. This condition was indicated by the solubilized phosphate content in the planting medium, which was higher in the application of Rhizobium spp compared to the control. Inoculation of Rhizobium spp from several rhizospheres showed a significant effect on plant height, stem diameter, ear weight without husks, and ear dry weight compared to control. These bacteria are able to trigger the growth of maize through direct and indirect mechanisms. In addition, the plant height that was treated with maize-rhizosphere Rhizobium spp was better than rice. It is suspected that Rhizobium spp from the maize rhizosphere is more adaptable when applied to growing media for maize crops, so that it can increase plant height.
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Hegde, Dileep, Sunith Mahantheshappa, Jayarama Reddy, and Praveen Kumar Nagadesi. "Soil Microflora in Rhizosphere of Barringtonia racemosa (L.) Spreng and Rauwolfia serpentina (L.) Benth. ex Kurz from Western Ghats region of Uttara Kannada. Karnataka, India." Saudi Journal of Pathology and Microbiology 7, no. 7 (July 5, 2022): 254. http://dx.doi.org/10.36348/sjpm.2022.v07i07.001.
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A study was conducted for the isolation and identification of soil micro-flora in rhizosphere of B. racemosa (L.) Spreng and R. serpentine (L.) Benth. ex Kurz, trees from Western Ghats region of Uttar Kannada, Karnataka, India. Soil samples were collected from rhizosphere of B. racemosa and R. serpentine plants, during the months of February 2022. Soil microbes were isolated by using soil dilution technique. The total number of bacteria isolated from B. racemose and R. serpentinais rhizosphere is 2,666,600 and 4,461,160 per gram of soil respectively. The rhizospheric fungal isolates present in B. racemosa and R. serpentina plants is 3,281,200 and 1,946,200 per gram of soil respectively. In B. racemosa rhizosphere, the percentage contribution is Penicillium sp with 13.679%, In R. serpentine rhizosphere, the highest percentage contribution is Cladosporium sp., Trichoderma sp.with17.663% and 17.391% respectively. In rhizosphere of B. racemose, 19 different species belonging to 15 genera were isolated; among which Penicillium species is dominating over other fungal species isolated. In rhizosphere of R. serpentina, 18 different species belonging to 11 genera were observed; among which Trichoderma sp.is dominating over other fugal species isolates. The most frequently isolated fungi from the rhizosperes of B. racemosa and R. serpentine plants are Penicillium sp and Trichoderma sp.For the first time the rhizospheric micro-flora i.e., bacteria and fungi was reported from B. racemose soil sample collected from Western Ghats region of Uttara Kannada. For the first time the rhizospheric myco-flora was reported from R. serpentine soil samples collected from Western Ghats region of Uttara Kannada. All the bacteria and fungi isolated was new report to Wester Ghats region of Uttar Kannada, Karnataka, India.
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Shaikh, Mosma Nadim, and Digambar Nabhu Mokat. "Role of Rhizosphere Fungi Associated with Commercially Explored Medicinal and Aromatic Plants: A Review." Current Agriculture Research Journal 6, no. 1 (April 10, 2018): 72–77. http://dx.doi.org/10.12944/carj.6.1.09.
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The study of rhizospheric microbial flora for the enhancement of aroma compounds is well recognized. The rhizosphere microbes also play very important role in improving medicinal values of plants. Rhizospheric microbes affect the plant physiology by imparting several useful effects such as nitrogen fixation, nutrient uptake, and production of secondary metabolites in the medicinal and aromatic plants. Recent days there are increasing the interests in the research of the relation between rhizosphere microbes associated with medicinal plant for the improvement of quality of medicinal plants. A large variety of fungi and bacteria is recognized in the rhizosphere soil of medicinal plants that showed significant effect in secondary metabolite alteration and uptake of plant nutrient. There are reports that rhizosphere fungi not only enhanced the growth parameters in plants but also considerably modulated essential oil’s quality. This study highlighted the researches performed on active role of rhizosphere fungi on explored medicinal and aromatic plants. As the use of organic material is one of the constituents of good agricultural practices (GAPs). Therefore, this review also investigates the environmental concerns reducing the use harmful chemicals as well as recommendation for utilization of biological and organics in agriculture. Therefore, a proper understanding of role of rhizosphere mycoflora associated with the medicinal plants is essential.
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Muratova, A. Yu, N. A. Zelenova, I. Yu Sungurtseva, S. V. Gorelova, A. P. Kolbas, and Ye V. Pleshakova. "Comparative Study of the Rhizospheric Microflora of Sunflower Cultivars Helianthus annuus (Asteráceae, Magnoliópsida) Grown on Soils with Anthropogenic Polyelemental Anomalies." Povolzhskiy Journal of Ecology, no. 4 (January 13, 2021): 442–58. http://dx.doi.org/10.35885/1684-7318-2020-4-442-458.
Full textAbstract:
In a laboratory pot experiment, two mutant cultivars of sunflower (Helianthus annuus cv. r2p2 and Helianthus annuus cv. r5n1) were grown on soils with anthropogenic polyelemental anomalies and on a background control soil, and a comparative analysis of their rhizospheric microflora was carried out. The numbers of soil bacteria, actinomycetes and micromycetes, as well as the numbers of rhizospheric microorganisms resistant to Zn2+, Pb2+, and Cu2+ ions were estimated in the rhizosphere of sunflower cultivars. Quantitative changes in the sunflower rhizospheric microboceno-ses, formed under the influence of both the plant genotype and technogenic soil pollution, were revealed. A pronounced stimulation of the rhizospheric microorganisms of all groups studied was found when plants were cultivated on the technogenically contaminated soil from PJSC Kosogorsk Metallurgical Plant. In this case, cultivar differences were observed, namely: the maximal number of bacteria and actinomycetes was revealed in the rhizosphere of H. annuus cv. r2p2, whilst the maximal number of micromycetes was revealed in the rhizosphere of H. annuus cv. r5n1. An increased number of microorganisms resistant to lead ions was revealed in the rhizosphere of H. annuus cv. r2p2. The observed changes in the structure of rhizospheric microbial communities of the sunflower cultivars manifested in the stimulation of the growth and activity of soil microflora can be in demand for phytoremediation of technogenically contaminated soil.
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Brasil, Edilson Carvalho, Vera Maria Carvalho Alves, Ivanildo Evódio Marriel, Gilson Villaça Exel Pitta, and Janice Guedes de Carvalho. "Rhizosphere properties of maize genotypes with contrasting phosphorus efficiency." Revista Brasileira de Ciência do Solo 35, no. 1 (February 2011): 171–81. http://dx.doi.org/10.1590/s0100-06832011000100016.
Full textAbstract:
An experiment was conducted in a growth chamber to evaluate characteristics of the rhizosphere of maize genotypes contrasting in P-use efficiency, by determining length and density of root hairs, the rhizosphere pH and the functional diversity of rhizosphere bacteria. A sample of a Red Oxisol was limed and fertilized with N, K and micronutrients. In the treatment with the highest P level, 174 mg kg-1 P was added. Each experimental unit corresponded to a PVC rhizobox filled with 2.2 dm-3 soil. The experiment was completely randomized with three replications in a 5 x 2 factorial design, corresponding to five genotypes (H1, H2 and H3 = P-efficient hybrids, H4 and H5 = P-inefficient hybrids) and two P levels (low = 3 mg dm-3, high = 29 mg dm-3). It was found that 18 days after transplanting, the nodal roots of the hybrids H3 and H2 had the longest root hairs. In general, the pH in the rhizosphere of the different genotypes was higher than in non-rhizosphere soil, irrespective of the P level. The pH was higher in the rhizosphere of lateral than of nodal roots. At low P levels, the pH variation of the hybrids H2, H4 and H5 was greater in rhizospheric than in non-rhizospheric soil. The functional microbial activity in the rhizosphere of the hybrids H3 and H5 was highest. At low soil P levels, the indices of microbial functional diversity were also higher. The microbial metabolic profile in the rhizosphere of hybrids H1, H2, H3, and H5 remained unaltered when the plants were grown at low P. The variations in the rhizosphere properties could not be related to patterns of P-use efficiency in the tested genotypes.
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Woźniak, Małgorzata, Jarosław Grządziel, Anna Gałązka, and Magdalena Frąc. "Metagenomic analysis of bacterial and fungal community composition associated with Paulownia elongata × Paulownia fortunei." BioResources 14, no. 4 (September 12, 2019): 8511–29. http://dx.doi.org/10.15376/biores.14.4.8511-8529.
Full textAbstract:
The dynamics and interactions of microbial communities in Paulownia’s life cycle are poorly understood. The main goal of this study was to compare the rhizospheric soil and endophytic microbiome and mycobiome of hybrid Paulownia elongata and Paulownia fortunei. The comparison was based on highly efficient Illumina MiSeq sequencing of bacteria and fungi from the rhizosphere and endosphere of bioenergetic trees P. elongata x P. fortunei. The general richness of bacteria and rhizospheric fungi (based on Chao 1, Shannon, and Simpson indicators) was higher than in endosphere samples from the same plants. Actinobacteria and Proteobacteria were dominant in the rhizosphere and endosphere of plants in healthy conditions. The rhizosphere fungal communities in both trials were dominated by Ascomycota, Mortierellomycota, and Basidiomycota. Most root endophytes came from Olpidiomycota, Oomycota, and Ascomycota, while most leaf endophytes were from Ascomycota and Basidiomycota. This study was the first report on the composition of bacteria and fungi associated with the endosphere and rhizosphere of Paulownia trees. These studies showed that bacterial and fungal communities from the rhizosphere and endosphere were separate communities. It also showed that the health conditions of trees did not affect the composition of endophytic microorganisms in Paulownia tissues.
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Huang, Xing-Feng, Jacqueline M. Chaparro, Kenneth F. Reardon, Ruifu Zhang, Qirong Shen, and Jorge M. Vivanco. "Rhizosphere interactions: root exudates, microbes, and microbial communities." Botany 92, no. 4 (April 2014): 267–75. http://dx.doi.org/10.1139/cjb-2013-0225.
Full textAbstract:
The study of the interactions between plants and their microbial communities in the rhizosphere is important for developing sustainable management practices and agricultural products such as biofertilizers and biopesticides. Plant roots release a broad variety of chemical compounds to attract and select microorganisms in the rhizosphere. In turn, these plant-associated microorganisms, via different mechanisms, influence plant health and growth. In this review, we summarize recent progress made in unraveling the interactions between plants and rhizosphere microbes through plant root exudates, focusing on how root exudate compounds mediate rhizospheric interactions both at the plant–microbe and plant–microbiome levels. We also discuss the potential of root exudates for harnessing rhizospheric interactions with microbes that could lead to sustainable agricultural practices.
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Sui, Junkang, Jiayi Yang, Chenyu Li, Lingxiao Zhang, and Xuewen Hua. "Effects of a Microbial Restoration Substrate on Plant Growth and Rhizosphere Microbial Community in a Continuous Cropping Poplar." Microorganisms 11, no. 2 (February 15, 2023): 486. http://dx.doi.org/10.3390/microorganisms11020486.
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In poplar cultivation, continuous cropping obstacles affect wood yield and soil-borne diseases, primarily due to structural changes in microbes and fungus infection. The bacterium Bacillus cereus BJS-1-3 has strong antagonistic properties against pathogens that were isolated from the rhizosphere soil of poplars. Poplar rhizospheres were investigated for the effects of Bacillus cereus BJS-1-3 on microbial communities. Three successive generations of soil were used to replant poplar seedlings. BJS-1-3 inoculated poplars were larger, had higher plant height and breast height diameter, and had a greater number of total and culturable bacteria than non-inoculated controls. B. cereus BJS-1-3 inoculated poplar rhizospheres were sequenced, utilizing the Illumina MiSeq platform to analyze changes in diversity and structure. The fungi abundance and diversity in the BJS-1-3 rhizosphere were significantly lower than in the control rhizosphere. In comparison to the control group, Bacillus sp. constituted 2.87% and 2.38% of the total bacterial community, while Rhizoctonia sp. constituted 2.06% and 6.00% of the total fungal community. Among the potential benefits of B. cereus BJS-1-3 in poplar cultivation is that it enhances rhizosphere microbial community structure and facilitates the growth of trees.
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Miah, Md Yunus, Nusrat Jahan Rubaida, Mohammed Zia Uddin Kamal, Md Humayun Kabir, Mohammed Abdus Salam, Toru Fujiwara, Ming Kwang Wang, and Karl Imberger. "Rhizobox Technology for Sustainable Agriculture–Acquired Implications." European Journal of Agriculture and Food Sciences 6, no. 2 (April 17, 2024): 39–45. http://dx.doi.org/10.24018/ejfood.2024.6.2.775.
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Evaluation on the effect of rhizobox technology in the rhizosphre soil of agricultural crops is necessary for sound and safe agriculture. This article confers the rhizobox technology-induced information about rhizosphere so far conducted since 1987s and on. Combined with its special features and construction technique, rhizobox-affected rhizosphere processes like pH changes, patterns of nutrient distribution, heavy metal movement and microbial activities are extensively analyzed. Finally, the established rhizobox model of 1987 encompassing its modified versions are detailed, followed by its potential application in rhizosphere studies of plant nutrition, soil chemistry, and soil biology for sustainable agriculture.
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Handique, Mridupol, Popy Bora, Vasileios Ziogas, Anoop Kumar Srivastava, Prasanth Tej Kumar Jagannadham, and Asish Kumar Das. "Phytophthora Infection Reorients the Composition of Rhizospheric Microbial Assembly in Khasi Mandarin (Citrus reticulata Blanco)." Agronomy 14, no. 4 (March 24, 2024): 661. http://dx.doi.org/10.3390/agronomy14040661.
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Phytophthora gummosis, foot rot, and root rot are considered major challenges to the citrus industry worldwide. Little is known about the Phytophthora–microbiome interaction, despite several studies demonstrating changes in the microbial composition of the rhizosphere following challenges by a pathogen. In the present study, we studied the microbial diversity and community structure in healthy rhizospheres and Phytophthora-infected rhizospheres of Khasi mandarin (Citrus reticulata Blanco), a commercial cultivar extensively grown in the northeast of India. An exploratory study was conducted to identify Phytophthora-infected orchards of Khasi mandarin, and the isolated pathogen was confirmed as P. nicotianae based on its morpho-cultural and molecular characteristics coupled with pathogenicity tests. This study on culturable microbes established the dominance of Trichoderma spp. in the healthy rhizosphere, while the diseased rhizosphere showed the presence of Fusarium spp. A metagenomic study further revealed that the rhizospheres of Phytophthora-infected plants were dominated by species such as Bacteroidia spp., Patescibacteria spp., and Pythium spp., while the healthy Khasi mandarin rhizospheres had a more diverse community predominantly represented by Trichoderma, Penicillium, Linnemannia, Mortierella, Talaromyces, Saitozyma, Bacteroidetes, Pseudomonas, Cytophagia, Cyanobacteria, Bacteroidia, Sphingobacteriia, Burkholderia, Bacillus, and Bradyrhizobium. Terrabacteria and FCB (Fibrobacterota, Chlorobiota, and Bacteroidota groups) were found to exist in higher relative abundance in disease-free soils than in Phytophthora-infected soils, while phylum Proteobacteria showed identical relative abundance in all soil types. The phyla represented by Pseudomonas, Flavobacteriia, Candidatus, Mycobacterium, Rhizobium, Mesorhizobium, Sphingomonas, and Cytophagia were the most common bacterial phyla in all soil samples, but healthy soil exhibited a greater abundance of Bacteroidetes, Pseudomonas, Cytophagia, Cyanobacteria, Bacteroidia, Sphingobacteriia, Burkholderia, Bacillus, and Bradyrhizobium. Our study suggests that the presence of Phytophthora spp. in the rhizosphere alters microbial community structure, having potentially strong implications for plant health and productivity. These rhizosphere microbiome-derived citrus responses shed light on exploring effective management strategies for Phytophthora gummosis disease ailing Khasi mandarin.
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McKenzie, R. H., J. F. Dormaar, G. B. Schaalje, and J. W. B. Stewart. "Chemical and biochemical changes in the rhizospheres of wheat and canola." Canadian Journal of Soil Science 75, no. 4 (November 1, 1995): 439–47. http://dx.doi.org/10.4141/cjss95-064.
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Short-term root processes can influence chemical and biochemical conditions at the soil–plant–root interface. In this study, soil phosphorus forms, pH and biochemical properties within and adjacent to the rhizosphere of hard red spring wheat (Triticum aestivum L. ’Katepwa’) and canola (Brassica napus L. ’Westar’) seedlings were studied over a 5-wk period. Soils were from the Ap horizon of a Calcareous Dark Brown Chernozemic soil (Lethbridge, Alta) and an Orthic Gray Luvisolic soil (Breton, Alta) obtained from fertilized and unfertilized long-term continuous-cropped and wheat–fallow rotation plots. Wheat and canola both absorbed more total phosphorus (P), produced more aboveground material and had higher dehydrogenase and alkaline phosphatase activities when grown in Lethbridge soils than when grown in Breton soils. Canola took up more P from both the resin-extractable inorganic P (resin-Pi) and hydrochloric acid extractable (HCl-Pi) fractions than wheat, indicating a greater ability to extract P from soil. Acid phosphatase levels increased over time in the rhizospheres of both wheat and canola. Dehydrogenase activity was greater in the rhizospheres of wheat than of canola, indicating greater microbial activity. Canola roots frequently lowered pH within their rhizosphere which apparently suppressed microbial activity. Dehydrogenase activity in the relatively acidic Luvisolic soils was lower than in the near-neutral Chernozemic soils. The plant-root chemical and biochemical changes in the rhizosphere varied depending on soil chemical characteristics and past soil management history. Results showed canola and wheat utilize different mechanisms to influence their root rhizospheres and obtain their nutritional requirements. Rhizosphere changes were a function of plant species, soil type and previous soil management history. Key words: Rhizosphere, pH, phosphatase, dehydrogenase, P bioavailability, soil phosphorus transformations, wheat, canola
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Zhang, Siyu, Yue An, Yu Zhou, Xiaofang Wang, Yiqing Tang, Daorong Zhang, Genlou Sun, Qifei Wang, and Xifeng Ren. "Bacterial Community Structure in Rhizosphere of Barley at Maturity Stage." Agronomy 13, no. 11 (November 16, 2023): 2825. http://dx.doi.org/10.3390/agronomy13112825.
Full textAbstract:
The crop rhizosphere is the main site of soil microbial activities. Understanding the structure and diversity of microbial communities in the crop rhizosphere will help us reveal interactions between rhizosphere microorganisms and plant growth. In this study, the rhizosphere soil was collected from 35 cultivated barley varieties at the mature stage. To investigate the structure and diversity of bacterial communities in the rhizosphere of different barley varieties, the 16S rDNA gene of microorganisms from the soil was sequenced using Illumina MiSeq next-generation high-throughput sequencing technology. The results showed that 13, 25, 49, and 59 bacterial flora with relative abundance >1% were detected from 35 barley rhizosphere samples at the phylum, class, order, and family levels, respectively. The abundance of bacteria among varieties differed relatively little, but the abundance of the same bacteria in rhizospheres of different varieties was different. In addition, both the cluster analysis and principal component analysis (PCA) divided the 35 samples into three clusters at the phylum level. Groups III and IV showed significantly higher abundance than group II in Proteobacteria, while group II exhibited significantly higher abundance of Chloroflexi than groups III and IV. This finding provides a realistic basis for further using the relationship between barley rhizosphere microorganisms and barley growth to improve the resistance and quality of barley.
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Alawiye, Temitayo, and Olubukola Babalola. "Metagenomic Insight into the Community Structure and Functional Genes in the Sunflower Rhizosphere Microbiome." Agriculture 11, no. 2 (February 18, 2021): 167. http://dx.doi.org/10.3390/agriculture11020167.
Full textAbstract:
The rhizosphere’s microbial communities consist of a diverse set of microorganisms that can be beneficial to plants. These beneficial microorganisms are key determinants of plant productivity and health. In this study, we used shotgun metagenomics to explore and characterize the microbiome of the sunflower rhizosphere and bulk soil. The rhizosphere shared features with the bulk soil with dominant phyla such as Actinobacteria, Proteobacteria, Acidobacteria, Bacteroidetes, Planctomycetes, and Verrucomicrobia. There was no significant difference in the alpha diversity of the sunflower rhizosphere and bulk soils, though diversity was lower in the rhizosphere, suggesting a selection of microorganisms by sunflower rhizosphere to the bulk soil community. The genes present in the rhizosphere with their corresponding proteins as observed in our study conferred potential plant-beneficial properties such as siderophore production, nitrogen fixation, phosphate solubilizing, 1-aminocyclopropane-1-carboxylate (ACC) deaminase. Furthermore, other genes such as exopolysaccharides-producing, high-temperature stress response, and heat and cold shock response genes, which help withstand environmental stresses were also identified more in the rhizosphere. Of note from our study is the gene phenazine biosynthesis protein, which confers biocontrol. With the current indiscriminate use of pesticides that are considered harmful to the ecosystem, these potential functional genes can be further exploited and used as a biotechnological application for sustainable agriculture.
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Tang, Zichao, Yanxue Jiang, Chenchen Wang, Rui Zhang, Jinsong Guo, and Fang Fang. "New Insight into Phosphorus Release of Rhizosphere Soil in the Water Level Fluctuation Zone." Sustainability 15, no. 8 (April 13, 2023): 6635. http://dx.doi.org/10.3390/su15086635.
Full textAbstract:
Many phosphorus release experiments have been conducted in the water level fluctuation zone (WLFZ). However, the effects of rhizospheres on the risk of soil phosphorus release remain unclear. In this study, twenty-four soil samples were collected from the WLFZ of the Pengxi River, the largest tributary of the northern Three Gorges Reservoir. Physicochemical properties, phosphorus forms and phosphatase activity in rhizosphere and near-rhizosphere soils were investigated. Both the total phosphorus (TP) and water-extracted organic phosphorus (H2O-Po) contents were significantly higher in rhizosphere soils than in near-rhizosphere soils (p < 0.05). Enrichment rates (ER) of TP and H2O-Po were 42.4% and 180.3%, respectively. Significant increases were also found in activities of acid phosphatase, alkaline phosphatase, and phosphodiesterase in the rhizosphere, and corresponding ERs were 95.3%, 76.1%, and 22.0%, respectively. Environmental factors, such as pH, organic matter, and amorphous manganese, made significant contributions to the variations of phosphorus forms and phosphatase activities. The risk of phosphorus release to water in the rhizosphere soils of the study area increased slightly, according to the water-extracted phosphorus index. This risk may further increase due to flooding, as plant uptake of soil phosphorus would be inhibited while inorganic phosphorus is still generated by phosphatase.
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Zhou, Yan, Jing Li, Qi Tong, and Changli Zeng. "Community Structures and Dynamic Changes of Rhizosphere Microorganisms of Rhododendron agastum at Different Ages." Journal of Biobased Materials and Bioenergy 16, no. 5 (October 1, 2022): 729–36. http://dx.doi.org/10.1166/jbmb.2022.2230.
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This research aimed at studying the community structural characteristics and changes of rhizospheric microorganisms of Rhododendron agastum at different ages to provide useful information for introduction, domestication, and growth management of R. agastum. The rhizosphere bacterial and fungal communities of R. agastum were sequenced. Meanwhile, the richness and diversity indexes in the V3–V4 regions of bacterial 16S rRNA genes and internal transcribed spacer (ITS) region of fungi were investigated. Results showed that, R. agastum at different ages differs in the rhizospheria microbial community structure. The Shannon, ACE index, and Chao1 index of rhizospheria bacterial and fungal communities of 6-year-old R. agastum are all higher than those of 1- and 3-year-old ones. A total of 7,493 bacterial operational taxonomic units (OTUs) were obtained in root samples of R. agastum at different ages, covering 402 genera, which belong to 169 families, 98 order, 64 classes, and 23 phyla. The dominant rhizospheria bacterial communities of R. agastum included Proteobacteria, Actinobacteria, and Acidobacteria. Meanwhile, 1,583 fungal OTUs were obtained, belonging to 226 genera, 126 families, 89 orders, 38 classes, and 12 phyla, and the dominant fungal communities included Ascomycota, Basidiomycota, and Glomeromycota. The root system of R. agastum has abundant rhizospheria microorganisms, ample microbial OTUs and specific OTUs. With increased planting years of R. agastum, Proteobacteria and Actinobacteria displayed decreased and then increased trend. Bacteroidete was reduced year by year, and Acidobacteria showed increased and then decreased trend in bacterial communities. As for fungi, Ascomycota and Glomeromycota both exhibited decreased trend. Changes in rhizospheric microorganisms are probably an important factor that influences the growth of R. agastum, and rhizospheric microorganisms play a significant ecological role in maintaining growth of the plant.
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Liu, Xiaojing, Fengfeng Du, Shaozhou Chen, Naiwei Li, Jian Cui, Yajun Chang, Linhe Sun, Jinfeng Li, and Dongrui Yao. "Increased Diversity of Rhizosphere Bacterial Community Confers Adaptability to Coastal Environment for Sapium sebiferum Trees." Forests 13, no. 5 (April 26, 2022): 667. http://dx.doi.org/10.3390/f13050667.
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Sapium sebiferum (L.) Roxb. is an economically important tree in eastern Asia, and it exhibits many traits associated with good forestation species in coastal land. However, scarce research has been conducted to elucidate the effects of rhizosphere bacterial diversity on the adaptability and viability of S. sebiferum trees grown in the coastal environment. Field trials were conducted, and rhizosphere soil samples were collected from typical coastal and forestry nursery environments. Rhizosphere bacterial communities were evaluated using 16S rRNA pyrosequencing. A total of 43 bacterial phyla were detected in all the coastal and nursery rhizospheric soil samples. Relatively higher rhizosphere community diversity was found in coastal field-grown trees. Proteobacteria, Acidobacteriota, Bacteroidota, Chloroflex, and Gemmatimonadota were dominant bacterial phyla in rhizosphere communities of tallow trees. However, the rare groups in the coastal rhizosphere soils, with a relative abundance lower than 1%, including Latescibacterota, Methylomirabilota, NB1-j, and Nitrospirota, were largely absent in the nursery field-grown tree’s rhizosphere soils. LEfSe analysis identified a total of 43 bacterial groups that were more significantly abundant in the coastal rhizosphere environment than in that of forestry nursery grown trees. Further, our cladogram analysis identified Nitrospirota, Methylomirabilota, NB1-j, and Latescibacterota as biomarkers for the coastal environment at the phylum taxonomic level. These results suggested that the adaptability of S. sebiferum trees in coastal environment might be promoted by rhizosphere microbial interactions. Complex tree–microbe interactions might enhance the resistance of the trees to coastal environment, partially by recruiting certain bacterial microbiome species, which is of high saline-alkali resistance.
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Liu, Xiaojing, Fengfeng Du, Shaozhou Chen, Naiwei Li, Jian Cui, Yajun Chang, Linhe Sun, Jinfeng Li, and Dongrui Yao. "Increased Diversity of Rhizosphere Bacterial Community Confers Adaptability to Coastal Environment for Sapium sebiferum Trees." Forests 13, no. 5 (April 26, 2022): 667. http://dx.doi.org/10.3390/f13050667.
Full textAbstract:
Sapium sebiferum (L.) Roxb. is an economically important tree in eastern Asia, and it exhibits many traits associated with good forestation species in coastal land. However, scarce research has been conducted to elucidate the effects of rhizosphere bacterial diversity on the adaptability and viability of S. sebiferum trees grown in the coastal environment. Field trials were conducted, and rhizosphere soil samples were collected from typical coastal and forestry nursery environments. Rhizosphere bacterial communities were evaluated using 16S rRNA pyrosequencing. A total of 43 bacterial phyla were detected in all the coastal and nursery rhizospheric soil samples. Relatively higher rhizosphere community diversity was found in coastal field-grown trees. Proteobacteria, Acidobacteriota, Bacteroidota, Chloroflex, and Gemmatimonadota were dominant bacterial phyla in rhizosphere communities of tallow trees. However, the rare groups in the coastal rhizosphere soils, with a relative abundance lower than 1%, including Latescibacterota, Methylomirabilota, NB1-j, and Nitrospirota, were largely absent in the nursery field-grown tree’s rhizosphere soils. LEfSe analysis identified a total of 43 bacterial groups that were more significantly abundant in the coastal rhizosphere environment than in that of forestry nursery grown trees. Further, our cladogram analysis identified Nitrospirota, Methylomirabilota, NB1-j, and Latescibacterota as biomarkers for the coastal environment at the phylum taxonomic level. These results suggested that the adaptability of S. sebiferum trees in coastal environment might be promoted by rhizosphere microbial interactions. Complex tree–microbe interactions might enhance the resistance of the trees to coastal environment, partially by recruiting certain bacterial microbiome species, which is of high saline-alkali resistance.
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Liu, Xiaojing, Fengfeng Du, Shaozhou Chen, Naiwei Li, Jian Cui, Yajun Chang, Linhe Sun, Jinfeng Li, and Dongrui Yao. "Increased Diversity of Rhizosphere Bacterial Community Confers Adaptability to Coastal Environment for Sapium sebiferum Trees." Forests 13, no. 5 (April 26, 2022): 667. http://dx.doi.org/10.3390/f13050667.
Full textAbstract:
Sapium sebiferum (L.) Roxb. is an economically important tree in eastern Asia, and it exhibits many traits associated with good forestation species in coastal land. However, scarce research has been conducted to elucidate the effects of rhizosphere bacterial diversity on the adaptability and viability of S. sebiferum trees grown in the coastal environment. Field trials were conducted, and rhizosphere soil samples were collected from typical coastal and forestry nursery environments. Rhizosphere bacterial communities were evaluated using 16S rRNA pyrosequencing. A total of 43 bacterial phyla were detected in all the coastal and nursery rhizospheric soil samples. Relatively higher rhizosphere community diversity was found in coastal field-grown trees. Proteobacteria, Acidobacteriota, Bacteroidota, Chloroflex, and Gemmatimonadota were dominant bacterial phyla in rhizosphere communities of tallow trees. However, the rare groups in the coastal rhizosphere soils, with a relative abundance lower than 1%, including Latescibacterota, Methylomirabilota, NB1-j, and Nitrospirota, were largely absent in the nursery field-grown tree’s rhizosphere soils. LEfSe analysis identified a total of 43 bacterial groups that were more significantly abundant in the coastal rhizosphere environment than in that of forestry nursery grown trees. Further, our cladogram analysis identified Nitrospirota, Methylomirabilota, NB1-j, and Latescibacterota as biomarkers for the coastal environment at the phylum taxonomic level. These results suggested that the adaptability of S. sebiferum trees in coastal environment might be promoted by rhizosphere microbial interactions. Complex tree–microbe interactions might enhance the resistance of the trees to coastal environment, partially by recruiting certain bacterial microbiome species, which is of high saline-alkali resistance.
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K., Kalaiselvi, D. Jayanthi, P. Santhy, M. Gnanachitra, and B. Gokila. "Effect of long term fertilization on phosphorus dynamics in root zone environment under finger millet - Maize cropping sequence." Journal of Applied and Natural Science 13, no. 4 (December 16, 2021): 1383–89. http://dx.doi.org/10.31018/jans.v13i4.3079.
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In an agro-ecosystem, phosphorus (P) is found in organic and an inorganic form which includes soluble P, sorbed P and mineral bounded P. In soil, added P sources undergo various soil processes like mineralization, immobilization, precipitation, weathering, dissolution, sorption and desorption. For understanding the P dynamics in clay loam (Vertic Ustropept) soil, the present study was undertaken in P dynamics under rhizosphere and non-rhizosphere environment of maize in Long Term Fertilizer Experiment at Tamil Nadu Agricultural University, Coimbatore. The results revealed that the fractions of various pools of inorganic NaOH extractable Fe - P, H2SO4 extractable Ca- P, NH4F extractable Al- P, NH4Cl extractable Saloid P and Na citrate - Dithionate extractable Reductant soluble P were dominant in the non-rhizospheric soil than rhizospheric environment. The order of inorganic P fractions in the non-rhizospheric and rhizospheric region of the soil was found as Ca-P > Fe-P > Al-P > Reductant soluble-P > Saloid P and the knee-high stage of the non - rhizosphere soil recorded the highest inorganic as well organic P fractions. Irrespective of P fractions, Ca – P was recorded high (192.5 & 186.7 mg kg-1 ) followed by Fe - P (40.8& 34.9 mg kg-1) at a knee-high stage in non-rhizosphere and rhizosphere, respectively. Practising various nutrient management systems, application of 100% recommended dose of fertilizer along with FYM @ 10 t ha-1 (T8) recorded significant changes in all inorganic (Ca-P, Fe-P, Al-P, Reductant soluble-P, Saloid P), organic fractions and also Total P followed by 150% NPK (T3) in sandy clay loam soil. Nowadays, increasing demand for P fertilizer in India, judicious use of P fertilizer is important. Despite that, intensively cultivated soils have a lot of P reserves like organic and inorganic P pools and effective way of P transformation management could reduce the quantum of P fertilization in soil.
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Patkowska, Elżbieta. "The influence of biostimulants on the rhizospheric microorganisms of scorzonera (Scorzonera hispanica L.)." Acta Scientiarum Polonorum Hortorum Cultus 22, no. 5 (October 30, 2023): 31–42. http://dx.doi.org/10.24326/asphc.2023.5056.
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Scorzonera (Scorzonera hispanica L.) is a particularly valuable species among little-known and rarely cultivated vegetables. It is a root vegetable of high dietary and nutritional values. The suitable microbiological activity of the soil favors the growth and development of scorzonera. Biostimulants can positively affect the communities of rhizospheric microorganisms of cultivated plants, including this important vegetable. The studies established the influence of biostimulants on the microbial communities in the scorzonera rhizosphere. Before setting up the field experiment, scorzonera seeds were dressed with fungicide Zaprawa Nasienna T 75 DS/WS or biostimulants Beta-Chikol, Bio-Algeen S-90, and Asahi SL. The laboratory microbiological analyses of scorzonera rhizosphere soil were conducted and determined the total population of bacteria and fungi. The obtained rhizosphere isolates of fungi Albifimbria, Clonostachys, Epicoccum, Penicillium, and Trichoderma sp. were tested to check the influence on fungi pathogenic to scorzonera (Fusarium culmorum, Fusarium oxysporum, Sclerotinia sclerotiorum, and Rhizoctonia solani). The experiments showed that biostimulants, especially Asahi SL and Beta-Chikol, favored the development of rhizobacteria populations (including Bacillus sp. and Pseudomonas sp.). All biostimulants (Beta-Chikol, in particular) and the fungicide decreased the population of rhizospheric fungi and limited the occurrence of polyphagous fungi in the rhizosphere of scorzonera. Biostimulant Beta-Chikol and fungicide Zaprawa Nasienna T 75 DS/WS were most effective in stimulating the development of antagonistic fungi. Clonostachys rosea, Trichoderma sp., and Albifimbria verrucaria predominated as antagonistic rhizospheric fungi.
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Ye, Fan, Miao Jiang, Peng Zhang, Lei Liu, Shengqun Liu, Chunsheng Zhao, and Xiangnan Li. "Exogenous Melatonin Reprograms the Rhizosphere Microbial Community to Modulate the Responses of Barley to Drought Stress." International Journal of Molecular Sciences 23, no. 17 (August 26, 2022): 9665. http://dx.doi.org/10.3390/ijms23179665.
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The rhizospheric melatonin application-induced drought tolerance has been illuminated in various plant species, while the roles of the rhizosphere microbial community in this process are still unclear. Here, the diversity and functions of the rhizosphere microbial community and related physiological parameters were tested in barley under the rhizospheric melatonin application and drought. Exogenous melatonin improved plant performance under drought via increasing the activities of non-structural carbohydrate metabolism enzymes and activating the antioxidant enzyme systems in barley roots under drought. The 16S/ITS rRNA gene sequencing revealed that drought and melatonin altered the compositions of the microbiome. Exogenous melatonin increased the relative abundance of the bacterial community in carbohydrate and carboxylate degradation, while decreasing the relative abundance in the pathways of fatty acid and lipid degradation and inorganic nutrient metabolism under drought. These results suggest that the effects of melatonin on rhizosphere microbes and nutrient condition need to be considered in its application for crop drought-resistant cultivation.
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Muratova, Anna, Svetlana Gorelova, Sergey Golubev, Dilyara Kamaldinova, and Murat Gins. "Rhizosphere Microbiomes of Amaranthus spp. Grown in Soils with Anthropogenic Polyelemental Anomalies." Agronomy 13, no. 3 (March 6, 2023): 759. http://dx.doi.org/10.3390/agronomy13030759.
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Study of rhizospheric microbial communities of plants growing under different environmental conditions is important for understanding the habitat-dependent formation of rhizosphere microbiomes. The rhizosphere bacterial communities of four amaranth cultivars were investigated in a laboratory pot experiment. Amaranthus tricolor cv. Valentina, A. cruentus cv. Dyuimovochka, and A. caudatus cvs. Bulava and Zelenaya Sosulka were grown for six months in three soils with different anthropogenic polyelemental anomalies and in a background control soil. After the plant cultivation, the rhizosphere soils were sampled and subjected to metagenomic analysis for the 16S rRNA gene. The results showed that the taxonomic structure of the amaranth rhizosphere microbiomes was represented by the dominant bacterial phyla Actinobacteriota and Proteobacteria. A feature of the taxonomic profile of the rhizobiomes of A. tricolor cv. Valentina and A. cruentus cv. Dyuimovochka was a large abundance of sequences related to Cyanobacteria. The formation of the amaranth rhizosphere microbiomes was largely unaffected by soils, but cultivar differences in the formation of the amaranth rhizosphere microbial structure were revealed. Bacterial taxa were identified that are possibly selected by amaranths and that may be important for plant adaptation to various habitat conditions. The targeted enrichment of the amaranth rhizosphere with members of these taxa could be useful for improving the efficacy of amaranth use for agricultural and remediation purposes.
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Muratova, Anna Yu, Svetlana V. Gorelova, Irina Yu Sungurtseva, and Nadezhda A. Zelenova. "Rhizospheric microbiomes of Sorghum bicolor grown on soils with anthropogenic polyelement anomalies." BIO Web of Conferences 23 (2020): 03008. http://dx.doi.org/10.1051/bioconf/20202303008.
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Comparative study was made of the rhizospheree microbiomes of two cultivars of sorghum (Sorghum bicolor cvs. Sucro 506 and Biomass 133) grown on soils with anthropogenic polyelement anomalies and on a background (control) soil. The study used traditional culture-based and culture-independent metagenomic approaches. In soils contaminated with heavy metals, we found decreased numbers of culturable bacteria and quantitative changes in the populations of actinomycetes and micromycetes. The relative abundance of the families whose members were able to resist heavy metals was found to increase in the rhizospheric communities. The taxonomic profile of the microbial communities at the phylum level did not differ significantly between cultivars. The Shannon diversity and the abundance of actinomycete families in the rhizosphere of cv. Biomass 133were greater than those for cv. Sucro 506. Significant differences were found between cultivars for the number of rhizospheric microorganisms resistant to heavy metals.
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Enagbonma, B. J., and P. O. Momoh. "PROFILING THE PHOSPHATE SOLUBILIZING AND NITROGEN-FIXING BACTERIA FROM THE RHIZOSPHERE OF Talinum fruticosum (L.) Juss." Open Journal of Environmental Research (ISSN: 2734-2085) 5, no. 1 (May 24, 2024): 14–23. http://dx.doi.org/10.52417/ojer.v5i1.632.
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Rhizospheric microorganisms play crucial roles in enhancing crop production and soil fertility maintenance and with little or no information on Talinum fruticosum rhizosphere microbiome. This research aimed to profile the phosphate-solubilizing and nitrogen-fixing bacteria (PSB and NFB) inhabiting the Talinum fruticosum rhizosphere, a common vegetable crop in many tropical and subtropical regions. Soils were extracted from the Talinum fruticosum plants grown in Ekosodin Secondary School Farm at Ekosodin, Benin City, Nigeria. Isolation and characterization of PSB and NFB were carried out using cultural, morphological and biochemical, media tests. Bacillus sp., Serratia sp., Enterobacter sp., and Alcaligenes sp. isolated from the Talinum fruticosum rhizosphere were screened for their phosphate solubilizing and nitrogen fixing abilities. Out of many isolates implicated in Talinum fruticosum rhizosphere, only Bacillus sp.was found to be positive for both nitrogen fixing and phosphate solubilization test while Enterobacter sp.was positive for only nitrogen fixing test. This study supports other studies that the rhizosphere of Talinum fruticosum hosts some plant growth-promoting bacteria which when harnessed may lead to sustainable agricultural strategies for improving crop yield.
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Ekyastuti, Wiwik, Dwi Astiani, Emi Roslinda, Hanna Artuti Ekamawanti, and Tri Widiastuti. "Population of Rhizosphere Bacteria on Several Species of Crops In The Tailings of Ex-Gold Mine." IOP Conference Series: Earth and Environmental Science 1153, no. 1 (May 1, 2023): 012024. http://dx.doi.org/10.1088/1755-1315/1153/1/012024.
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Abstract Tailings of ex-gold mines leave several environmental damage problems. Environmental damage causes disruption of microorganisms including bacteria. The revegetation of ex-gold mine tailings in Menjalin sub-district, Landak district, West Kalimantan has begun by local communities using agricultural crops. Women as farmers have an important role in the tailing revegetation process using agricultural crops. Therefore, women can help improve the tailings ecosystem as well as the family economy. The objective of the study was to detect the presence and density of bacterial populations in the rhizosphere of the revegetation crops. The research was conducted by survey method. Soil samples were taken compositely from the rhizosphere of four species of agricultural crops cultivated in tailings, i.e: Capsicum frutescens L., Solanum melongena, Ipomoea batatas L., and Manihot utilissima. The results showed that soil bacteria found growing well in the rhizospheres of four species crops. Two genera of bacteria were found in the tailing rhizosphere of ex-gold mine in Menjalin sub-district, namely Azotobacter and Pseudomonas. The bacterial population density in the rhizosphere of M. utilissima was significantly the highest. Meanwhile, the bacterial population density in the rhizosphere of C. frutescens, I. batatas, and S. melongena did not differ in the medium category. Further investigation found that the bacterial population in the rhizosphere of M. utilissima was 126.8 – 217 times denser than the other three crop species.
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Liu, Hongfei, Sha Xue, Guoliang Wang, and Guobin Liu. "Effects of nitrogen addition on soil oxidisable organic carbon fractions in the rhizospheric and bulk soils of Chinese pines in north-western China." Soil Research 56, no. 2 (2018): 192. http://dx.doi.org/10.1071/sr16358.
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Increased atmospheric nitrogen (N) deposition caused by human activities has potentially important effects on ecosystem carbon (C) dynamics and different effects on C fractions with different stabilities and chemical compositions. A better understanding of the responses of different C fractions to N addition is vital for maintaining soil quality and protecting vegetation. In order to investigate the differential effects of N addition on total soil organic carbon (SOC) and four SOC fractions with increasing degrees of oxidisability in Pinus tabuliformis rhizospheric and bulk soils, a 6-year pot experiment was performed testing the effects of the addition of N at rates of 2.8, 5.6, 11.2, 22.4 and 44.8 g m–2 year–1 compared with a control (CK) group (no N addition). Addition of N addition had significant (P < 0.05) effects on SOC fractions of very labile C (C1) and recalcitrant C (C4), but negligible effects on total SOC (TOC) and SOC fractions of labile C (C2) and less labile C (C3). The C1 content and ratio of C1 to TOC in rhizospheres decreased following the addition of low levels (N2.8–N5.6) of N, but increased after the addition of high levels (N11.2–N44.8) of N, with minimum values obtained after the addition of 11.2 N g m–2 year–1. Low rates (N2.8–N5.6) of N addition considerably increased C4 and the ratio of C4 to TOC in the rhizosphere, whereas addition of high rates (N11.2–N44.8) of N decreased these parameters. The responses of C1 and C4 in the bulk soil to N addition were opposite. The SOC fraction was significantly higher in the rhizosphere than in the bulk soil, indicating large rhizospheric effects. However, increased N addition weakened these effects. These findings suggest that low rates (N2.8–N5.6) of N addition stabilise SOC against chemical and biological degradation, whereas increased rates of N addition increase the lability of SOC in the bulk soil. Thus, the rhizosphere plays a vital role in soil carbon stability and sequestration in response to N addition.
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Takenaka, Shigehito, Hiroyuki Sekiguchi, Kazuhiro Nakaho, Motoaki Tojo, Akira Masunaka, and Hideki Takahashi. "Colonization of Pythium oligandrum in the Tomato Rhizosphere for Biological Control of Bacterial Wilt Disease Analyzed by Real-Time PCR and Confocal Laser-Scanning Microscopy." Phytopathology® 98, no. 2 (February 2008): 187–95. http://dx.doi.org/10.1094/phyto-98-2-0187.
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It recently has been reported that the non-plant-pathogenic oomycete Pythium oligandrum suppresses bacterial wilt caused by Ralstonia solanacearum in tomato. As one approach to determine disease-suppressive mechanisms of action, we analyzed the colonization of P. oligandrum in rhizospheres of tomato using real-time polymerase chain reaction (PCR) and confocal laser-scanning microscopy. The real-time PCR specifically quantified P. oligandrum in the tomato rhizosphere that is reliable over a range of 0.1 pg to 1 ng of P. oligandrum DNA from 25 mg dry weight of soil. Rhizosphere populations of P. oligandrum from tomato grown for 3 weeks in both unsterilized and sterilized field soils similarly increased with the initial application of at least 5 × 105 oospores per plant. Confocal microscopic observation also showed that hyphal development was frequent on the root surface and some hyphae penetrated into root epidermis. However, rhizosphere population dynamics after transplanting into sterilized soil showed that the P. oligandrum population decreased with time after transplanting, particularly at the root tips, indicating that this biocontrol fungus is rhizosphere competent but does not actively spread along roots. Protection over the long term from root-infecting pathogens does not seem to involve direct competition. However, sparse rhizosphere colonization of P. oligandrum reduced the bacterial wilt as well as more extensive colonization, which did not reduce the rhizosphere population of R. solanacearum. These results suggest that competition for infection sites and nutrients in rhizosphere is not the primary biocontrol mechanism of bacterial wilt by P. oligandrum.
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Gottel, Neil R., Hector F. Castro, Marilyn Kerley, Zamin Yang, Dale A. Pelletier, Mircea Podar, Tatiana Karpinets, et al. "Distinct Microbial Communities within the Endosphere and Rhizosphere of Populus deltoides Roots across Contrasting Soil Types." Applied and Environmental Microbiology 77, no. 17 (July 15, 2011): 5934–44. http://dx.doi.org/10.1128/aem.05255-11.
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ABSTRACTThe root-rhizosphere interface ofPopulusis the nexus of a variety of associations between bacteria, fungi, and the host plant and an ideal model for studying interactions between plants and microorganisms. However, such studies have generally been confined to greenhouse and plantation systems. Here we analyze microbial communities from the root endophytic and rhizospheric habitats ofPopulus deltoidesin mature natural trees from both upland and bottomland sites in central Tennessee. Community profiling utilized 454 pyrosequencing with separate primers targeting the V4 region for bacterial 16S rRNA and the D1/D2 region for fungal 28S rRNA genes. Rhizosphere bacteria were dominated byAcidobacteria(31%) andAlphaproteobacteria(30%), whereas most endophytes were from theGammaproteobacteria(54%) as well asAlphaproteobacteria(23%). A singlePseudomonas-like operational taxonomic unit (OTU) accounted for 34% of endophytic bacterial sequences. Endophytic bacterial richness was also highly variable and 10-fold lower than in rhizosphere samples originating from the same roots. Fungal rhizosphere and endophyte samples had approximately equal amounts of thePezizomycotina(40%), while theAgaricomycotinawere more abundant in the rhizosphere (34%) than endosphere (17%). Both fungal and bacterial rhizosphere samples were highly clustered compared to the more variable endophyte samples in a UniFrac principal coordinates analysis, regardless of upland or bottomland site origin. Hierarchical clustering of OTU relative abundance patterns also showed that the most abundant bacterial and fungal OTUs tended to be dominant in either the endophyte or rhizosphere samples but not both. Together, these findings demonstrate that root endophytic communities are distinct assemblages rather than opportunistic subsets of the rhizosphere.
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Murray, DIL. "Rhizosphere Microorganisms From the Jarrah Forest of Western Australia and Their Effects on Vegetative Growth and Sporulation in Phytophthora cinnamomi Rands." Australian Journal of Botany 35, no. 5 (1987): 567. http://dx.doi.org/10.1071/bt9870567.
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Soil dilution plate techniques were used to compare the numbers of bacteria, actinomycetes and fungi in the rhizospheres of Acacia pulchella, Banksia grandis and Eucalyptus marginata (jarrah). The most frequently isolated microorganisms and those detected in significantly different numbers in the rhizospheres of the three species were tested for their effects on sporangium production, zoospore discharge, zoospore germination and mycelial growth of the jarrah dieback pathogen Phytophthora cinnamomi. The total population of fungi in rhizosphere soil from B. grandis was much greater than that found in the rhizospheres of the other two species while the convesse was true for bacteria and actinomycetes, of which the largest populations were associated with A. pulchella. Penicillium spinulosum outnum- bered the combined population of other fungi in the Banksia rhizosphere but formed a much smaller proportion of the jarrah and Acacia rhizosphere microfloras, particularly the latter. P. spinulosum had no effect on mycelial growth or zoospore discharge in P. cinnamomi; it had some ability to stimulete sporangium production and, although it partly suppressed spore germination, the inhibitory effect was less pronounced than that noted for most other microorganisms. In contrast, microorganisms which strongly inhibited mycelial growth, zoospore discharge and germination represented a greater proportion of the Acacia rhizosphere microflora compared with the other microfloras, especially that of B. grandis. While some actinornycetes and fungi produced antibiotics that inhibited vegetative growth of P. cinnamomi in dual cultures, mycelial inhibition was often attributable to nutrient depletion of agar media by the test microorganisms. Similarly, nutrient deprivation resulting from microbial competition for substrates was also considered to be the stimulus for sporangium production in liquid media. The results are discussed in relation to previously reported suppression of P. cinnamomi in forest soils beneath stands of A. pulchella and the associated implications of this for biological control of jarrah dieback.
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Akhter, Kulsoom, Tahseen Ghous, Muhammad Siddique Awan, Zain Ul-Abdin, and Basharat Hussain. "High cadmium uptake ability of Bacillus cereus strains isolated from rhizosphere of Tagetes minuta L. growing in cadmium-polluted soil." Bangladesh Journal of Botany 47, no. 3 (October 28, 2018): 515–22. http://dx.doi.org/10.3329/bjb.v47i3.38720.
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Microbes resistant to heavy metals develop mechanisms to accumulate Cd(II) in their cells. Two bacterial strains, Bacillus cereus AVP12 and B. cereus NC7401 which grew at high Cd(II) concentration were isolated from roots of Tagetes minuta L. growing in Cd(II) contaminated and uncontaminated soil. Minimum inhibitory concentration (MIC) and percent removal capacity were determined as function of pH, contact time and initial Cd(II) concentration. Bioaccumulation capacity was determined to observe possible effect of two different rhizospheres on Cd(II) removal capacity of both strains. Both strains were resistant up to 300 mg/l Cd(II) concentration. The percent removal capacity of both strains was maximum at pH 7 and incubation time of 24 hrs. High bioaccumulation capacity was observed with increasing Cd(II) concentration. Both Langmuir and Freundlich models fitted well to data of Cd(II) bioaccumulation. Though, maximum adsorption capacity (Qo) was observed for strains isolated from both types of rhizospheres, however remarkable Qo values of 434.0 and 212.7 mg/g were observed for Bacillus cereus AVP12 and NC7401, respectively isolated from polluted rhizosphere. Bacillus cereus strains growing in polluted rhizosphere can develop high Cd(II) uptake ability in comparison to non-polluted rhizosphere.
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Morales-Manzo, Ivan I., Ana M. Ribes-Moya, Claudia Pallotti, Ana Jimenez-Belenguer, Clara Pérez Moro, María Dolores Raigón, Adrián Rodríguez-Burruezo, and Ana Fita. "Root–Soil Interactions for Pepper Accessions Grown under Organic and Conventional Farming." Plants 12, no. 9 (May 3, 2023): 1873. http://dx.doi.org/10.3390/plants12091873.
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Modern agriculture has boosted the production of food based on the use of pesticides and fertilizers and improved plant varieties. However, the impact of some such technologies is high and not sustainable in the long term. Although the importance of rhizospheres in final plant performance, nutrient cycling, and ecosystems is well recognized, there is still a lack of information on the interactions of their main players. In this paper, four accessions of pepper are studied at the rhizosphere and root level under two farming systems: organic and conventional. Variations in soil traits, such as induced respiration, enzymatic activities, microbial counts, and metabolism of nitrogen at the rhizosphere and bulk soil, as well as measures of root morphology and plant production, are presented. The results showed differences for the evaluated traits between organic and conventional management, both at the rhizosphere and bulk soil levels. Organic farming showed higher microbial counts, enzymatic activities, and nitrogen mobilization. Our results also showed how some genotypes, such as Serrano or Piquillo, modified the properties of the rhizospheres in a very genotype-dependent way. This specificity of the soil–plant interaction should be considered for future breeding programs for soil-tailored agriculture.
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Yang, Guang, Qing Zhang, Na Gong, and Yue Ma. "Effects of Different Fertilizers with Material Properties on Hot Pepper Growth and Microorganisms." Advanced Materials Research 788 (September 2013): 396–99. http://dx.doi.org/10.4028/www.scientific.net/amr.788.396.
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In this article, there was a comparison of effects of different applied fertilizers on hot pepper growth and rhizospheric microorganisms by field trial. It separated, cultivated, counted and initially identified bacteria, funguses and actinomycetes in different-pharmaceutics-treated rhizosphere soil by spread plate method. Results showed the significant difference among the quantities of bacteria, funguses and actinomycetes in hot pepper rhizosphere soil treated by different fertilizers, where there were the most bacteria, less actinomyceters, and a minimum of funguses. The application of fertilizer changed the rhizosphere microorganism environment of hot pepper, enhanced hot pepper plants to absorb the major nutritive elements, such as nitrogen and phosphorus, promoted hot pepper growth and increased its yield.
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Kowalski, Stefan, Hanna Stępniewska, Zbigniew Krzan, and Kazimierz Januszek. "The effect of contamination of soil by heavy metals on qualitative and quantitative composition of fungi in the rhizosphere of some forest trees." Acta Mycologica 33, no. 1 (August 20, 2014): 3–23. http://dx.doi.org/10.5586/am.1998.001.
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The effect of heavy metals in soils on the formation of fungal communities in the rhizosphere of different forest tree species was studied. Soil samples for heavy metal contamination tests and root samples for the determination of rhizospheric fungi were taken from the same root zone. The reduction of the quantitative as well as qualitative composition of fungi in the rhizosphere of individual tree species clearly correlated with the increase of soil contamination by Pb, Zn, end Cd. The following groups of fungi were distinguished: tolerant, very susceptible and relatively resistant to contamination of soil by heavy metals. Moreover a great influence of tree species on the qualitative and quantitative composition of fungi in the rhizosphere was demonstrated.
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Rosenzweig, N., J. M. Bradeen, Z. J. Tu, S. J. McKay, and L. L. Kinkel. "Rhizosphere bacterial communities associated with long-lived perennial prairie plants vary in diversity, composition, and structure." Canadian Journal of Microbiology 59, no. 7 (July 2013): 494–502. http://dx.doi.org/10.1139/cjm-2012-0661.
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The goal of this research was to investigate the variation in rhizosphere microbial community composition, diversity, and structure among individual Andropogon gerardii Vitman (big bluestem) and Lespedeza capitata Michx. (bush clover). Bacterial communities from the rhizosphere of 10 plants of each species (n = 20 plants total) were explored using a culture-independent pipeline. Microbial communities associated with both host plants had high bacterial diversity within individual plant rhizosphere and taxa unique to individual rhizospheres. Bacterial communities associated with the rhizosphere of A. gerardii were consistently more diverse than those associated with L. capitata, and there were significant differences between plant species in rhizosphere bacterial community composition. Differences included microbial taxa with no known functional relationship with their preferred host species, including sulfide-methylating obligate anaerobes (Holophaga), complete denitrifiers (Rhodoplanes), sludge inhabitants (Ktedonobacter), and nitrate oxidizers (Nitrospira). These results suggest the potential for plant species to have significant impacts on a broad array of ecosystem functions (e.g., cycling of carbon, nitrogen sulfurs, metals, and trace elements) via their selective impacts on soil microbes. However, sequence-based community analysis and the corresponding lack of intact microbial cultures limits understanding of the potential influences of enriched microbial taxa on plant hosts and their roles in ecosystem functioning.
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Bergsma-Vlami, M., M. E. Prins, M. Staats, and J. M. Raaijmakers. "Assessment of Genotypic Diversity of Antibiotic-Producing Pseudomonas Species in the Rhizosphere by Denaturing Gradient Gel Electrophoresis." Applied and Environmental Microbiology 71, no. 2 (February 2005): 993–1003. http://dx.doi.org/10.1128/aem.71.2.993-1003.2005.
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ABSTRACT The genotypic diversity of antibiotic-producing Pseudomonas spp. provides an enormous resource for identifying strains that are highly rhizosphere competent and superior for biological control of plant diseases. In this study, a simple and rapid method was developed to determine the presence and genotypic diversity of 2,4-diacetylphloroglucinol (DAPG)-producing Pseudomonas strains in rhizosphere samples. Denaturing gradient gel electrophoresis (DGGE) of 350-bp fragments of phlD, a key gene involved in DAPG biosynthesis, allowed discrimination between genotypically different phlD + reference strains and indigenous isolates. DGGE analysis of the phlD fragments provided a level of discrimination between phlD + genotypes that was higher than the level obtained by currently used techniques and enabled detection of specific phlD + genotypes directly in rhizosphere samples with a detection limit of approximately 5 × 103 CFU/g of root. DGGE also allowed simultaneous detection of multiple phlD + genotypes present in mixtures in rhizosphere samples. DGGE analysis of 184 indigenous phlD + isolates obtained from the rhizospheres of wheat, sugar beet, and potato plants resulted in the identification of seven phlD + genotypes, five of which were not described previously based on sequence and phylogenetic analyses. Subsequent bioassays demonstrated that eight genotypically different phlD + genotypes differed substantially in the ability to colonize the rhizosphere of sugar beet seedlings. Collectively, these results demonstrated that DGGE analysis of the phlD gene allows identification of new genotypic groups of specific antibiotic-producing Pseudomonas with different abilities to colonize the rhizosphere of sugar beet seedlings.