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1
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.
Анотація:
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.
2
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.
Анотація:
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.
3
Liu, Hong, Feifei Sun, Junwei Peng, Minchong Shen, Jiangang Li, and Yuanhua Dong. "Deterministic Process Dominated Belowground Community Assembly When Suffering Tomato Bacterial Wilt Disease." Agronomy 12, no. 5 (April 24, 2022): 1024. http://dx.doi.org/10.3390/agronomy12051024.
Анотація:
Soil microbial communities are closely associated with ecosystem functions. However, unravelling the complex nature of the microbial world and successfully utilizing all positive interactions for multipurpose environmental benefits is still a major challenge. Here, we describe the soil bacterial communities in different niches of healthy and diseased tomatoes under natural conditions. A higher abundance of the pathogen Ralstonia solanacearum and lower bacterial diversity were observed in the disease samples. The healthy tomato rhizosphere harbored more plant-beneficial microbes, including Bacillus and Streptomyces. Also, the co-occurrence network in the healthy rhizosphere samples was more complicated, so as to better adapt to the soil-borne pathogen invasion. Both the beta nearest-taxon-index (βNTI) and normalized stochasticity ratio (NST) analyses demonstrated that healthy rhizosphere communities were less phylogenetically clustered and mainly dominated by dispersal limitation, while homogeneous selection was the major assembly process driving the rhizosphere community of diseased samples. The results obtained with community assembly methods and co-occurrence network analysis revealed that healthy rhizosphere bacterial communities possessed potentially broader environmental stress (soil-borne pathogen stress) adaptability compared with diseased rhizosphere bacterial communities. In conclusion, this study contributed to widening our understanding of the potential mechanisms of soil bacterial community composition and assembly responding to soil-borne pathogen invasion.
4
Nyonita Punjungsari, Tyas, Agung Setya Wibowo, Intan Fuji Arriani, and Palupi Puspitorini. "EKSPLORASI KONSORSIUM PBRM (PLANT BENEFICIAL RHIZOSPHERIC MICROORGANISM) DALAM NUE (NUTRIENT USE EFFICIENCY) PADA PERTUMBUHAN JAGUNG (Zea mays L)." VIABEL: Jurnal Ilmiah Ilmu-Ilmu Pertanian 13, no. 2 (November 14, 2019): 11–15. http://dx.doi.org/10.35457/viabel.v13i2.836.
Анотація:
PBRM (Plant Beneficial Rhizospheric Microorganism) is a microbe that is able to form colonies in plant roots (rhizosphere) that have the ability to fix nitrogen (N), and dissolve potassium (K), phosphorus (P), and zinc (Zn).
Increasing NUE can increase plant growth through various mechanisms. Population and dynamics of rhizosphere microorganisms are different from other soil microorganisms, this is caused by an increase. The purpose of this study was to determine the type of rhizosphere bacteria that can be as PBRM. The method used The research was conducted at the Microbiology Laboratory of the Faculty of Agriculture, Brawijaya University, Malang. The characterization process was carried out in UB's microbiology laboratory. 50 grams of soil for planting corn were put into an erlenmeyer containing 500 ml NB (for bacteria) and 500 ml liquid PDA (for mold) and then incubated with the secretary for about 24 hours and then diluted in series to a dilution rate of 10-3,10-4,10 -5. Then from the dilution factor of 10-3,10-4,10-5 0.1 ml is taken and inoculated in solid media by the pour plate method. The results showed that the antagonistic rhizosphere bacteria were P. fluorescens, B. subtillis, and Rhizobium sp.
5
Elliott, Monica L., J. A. McInroy, K. Xiong, J. H. Kim, H. D. Skipper, and E. A. Guertal. "Taxonomic Diversity of Rhizosphere Bacteria in Golf Course Putting Greens at Representative Sites in the Southeastern United States." HortScience 43, no. 2 (April 2008): 514–18. http://dx.doi.org/10.21273/hortsci.43.2.514.
Анотація:
Taxonomic diversity of bacteria associated with golf course putting greens is a topic that has not been widely explored. The purpose of this project was to isolate and identify culturable bacteria from the rhizosphere of creeping bentgrass (Agrostris palustris Huds.) at two sites (Alabama and North Carolina) and hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] at two sites (Florida and South Carolina) for a minimum of 3 years with sampling initiated after the construction process. Randomly selected colonies were identified using gas chromatography for analysis of fatty acid methyl ester profiles. Over 9000 isolates were successfully analyzed. When a similarity index of 0.300 or higher was used, the average number of unidentifiable isolates was 38.6%. The two dominant genera in both bentgrass and bermudagrass rhizospheres were Bacillus and Pseudomonas with Bacillus dominant in bermudagrass and Pseudomonas dominant or equal to Bacillus in bentgrass. Other genera that comprised at least 1% of the isolates at all four sites were Clavibacter, Flavobacterium, and Microbacterium. Arthrobacter also comprised a significant portion of the bacterial isolates in the bentgrass rhizosphere, but not the bermudagrass rhizosphere. Overall, there were 40 genera common to all four sites. At the species level, there were five that comprised at least 1% of the isolates at each location: B. cereus, B. megaterium, C. michiganensis, F. johnsoniae, and P. putida. As has been reported for many grasses, we found considerable taxonomic diversity among the culturable bacterial populations from the rhizospheres of bentgrass and bermudagrass grown in sand-based putting greens.
6
Liu, Zhixiang, Jizhe Ying, and Chengcheng Liu. "Changes in Rhizosphere Soil Microorganisms and Metabolites during the Cultivation of Fritillaria cirrhosa." Biology 13, no. 5 (May 11, 2024): 334. http://dx.doi.org/10.3390/biology13050334.
Анотація:
Fritillaria cirrhosa is an important cash crop, and its industrial development is being hampered by continuous cropping obstacles, but the composition and changes of rhizosphere soil microorganisms and metabolites in the cultivation process of Fritillaria cirrhosa have not been revealed. We used metagenomics sequencing to analyze the changes of the microbiome in rhizosphere soil during a three-year cultivation process, and combined it with LC-MS/MS to detect the changes of metabolites. Results indicate that during the cultivation of Fritillaria cirrhosa, the composition and structure of the rhizosphere soil microbial community changed significantly, especially regarding the relative abundance of some beneficial bacteria. The abundance of Bradyrhizobium decreased from 7.04% in the first year to about 5% in the second and third years; the relative abundance of Pseudomonas also decreased from 6.20% in the first year to 2.22% in the third year; and the relative abundance of Lysobacter decreased significantly from more than 4% in the first two years of cultivation to 1.01% in the third year of cultivation. However, the relative abundance of some harmful fungi has significantly increased, such as Botrytis, which increased significantly from less than 3% in the first two years to 7.93% in the third year, and Talaromyces fungi, which were almost non-existent in the first two years of cultivation, significantly increased to 3.43% in the third year of cultivation. The composition and structure of Fritillaria cirrhosa rhizosphere metabolites also changed significantly, the most important of which were carbohydrates represented by sucrose (48.00–9.36–10.07%) and some amino acid compounds related to continuous cropping obstacles. Co-occurrence analysis showed that there was a significant correlation between differential microorganisms and differential metabolites, but Procrustes analysis showed that the relationship between bacteria and metabolites was closer than that between fungi and metabolites. In general, in the process of Fritillaria cirrhosa cultivation, the beneficial bacteria in the rhizosphere decreased, the harmful bacteria increased, and the relative abundance of carbohydrate and amino acid compounds related to continuous cropping obstacles changed significantly. There is a significant correlation between microorganisms and metabolites, and the shaping of the Fritillaria cirrhosa rhizosphere’s microecology by bacteria is more relevant.
7
Golestanifard, Alireza, Markus Puschenreiter, Amal Aryan, and Walter Wenzel. "Phosphorus depletion controls Cu and Zn biogeochemistry in canola and corn rhizosphere on a calcareous soil." Plant, Soil and Environment 67, No. 8 (August 12, 2021): 443–52. http://dx.doi.org/10.17221/122/2021-pse.
Анотація:
Phosphorus (P) deficiency may trigger rhizodeposition, including protons and organic compounds, with possible effects on metal solubility and speciation. To explore the relevance of this process, we investigated biogeochemical changes in the rhizosphere of P-deficient canola (Brassica napus L.) and corn (Zea mays L.) cultivars grown in a pot experiment on calcareous soil. Depletion of total soluble (0.005 mol/L Ca(NO3)2-extractable) P in the rhizosphere varied with crop species and cultivar but was generally strong and negatively correlated with dissolved organic carbon (DOC) in canola (R2 = 0.868) and corn (R2 = 0.844) rhizospheres, indicating rhizodeposition in response to limited P availability. DOC was correlated with dissolved Cu, explaining 86% of its variation in the rhizosphere and bulk soil solution of canola and corn cultivars, respectively, suggesting Cu mobilisation via the formation of Cu-organic complexes. In line with lower Zn-organic complex stabilities, the effect of rhizodeposition was less pronounced for Zn mobilisation. We show that the P nutritional status of plants and the related variation of rhizodeposition among crops and cultivars represents a major control of metal solubility in soil, with possible effects on micronutrient supply and toxicity. Hence, targeted P availability control should be considered in the management of polluted and micronutrient-deficient soils.
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Chowdhury, Saikat, Ramya Thangarajan, Nanthi Bolan, Julianne O'Reilly-Wapstra, Anitha Kunhikrishnan, and Ravi Naidu. "Nitrification potential in the rhizosphere of Australian native vegetation." Soil Research 55, no. 1 (2017): 58. http://dx.doi.org/10.1071/sr16116.
Анотація:
The rhizosphere influences nutrient dynamics in soil mainly by altering microbial activity. The objective of this study was to evaluate the rhizosphere effect on nitrogen transformation in Australian native vegetation in relation to nitrification potential (NP). Microbial activity, NP, and nitrifiers (ammonia-oxidising bacteria, AOB) were compared between rhizosphere and non-rhizosphere soils of several Australian native vegetation under field conditions. These parameters were also measured with increasing distance from the rhizosphere of selected plant species using plant growth experiments. To examine the persistence of nitrification inhibitory activity of rhizosphere soil on non-rhizosphere soil, the soils were mixed at various ratios and examined for NP and AOB populations. The rhizosphere soil from all native vegetation (29 species) had higher microbial activity than non-rhizosphere soil, whereas 13 species showed very low NP in the rhizosphere when compared with non-rhizosphere soil. Nitrification potential and AOB populations obtained in the soil mixture were lower than the predicted values, indicating the persistence of a nitrification inhibitory effect of the rhizosphere soils on non-rhizosphere soils. In plant growth experiments the microbial activity decreased with increasing distance from rhizosphere, whereas the opposite was observed for NP and AOB populations, indicating the selective inhibition of nitrification process in the rhizosphere of the Australian native plants Scaevola albida, Chrysocephalum semipapposum, and Enteropogon acicularis. Some Australian native plants inhibited nitrification in their rhizosphere. We propose future studies on these selected plant species by identifying and characterising the nitrification inhibiting compounds and also the potential of nitrification inhibition in reducing nitrogen losses through nitrate leaching and nitrous oxide emission.
9
Huang, Ning, Xingmin Zhao, Xinxin Guo, Biao Sui, Jinhua Liu, Hongbin Wang, and Jialin Li. "Tillage Methods Change Nitrogen Distribution and Enzyme Activities in Maize Rhizosphere and Non-Rhizosphere Chernozem in Jilin Province of China." Processes 11, no. 11 (November 20, 2023): 3253. http://dx.doi.org/10.3390/pr11113253.
Анотація:
The tillage method in farming systems is essential to develop strategies to increase fertilizer uptake by plant roots and to avoid environmental pollution. The field study aimed to investigate the characteristics of nitrogen and enzyme activities in rhizosphere soil with different tillage methods. Four treatment plots applied with fertilizers were established: continuous rotary tillage (CR), plowing-rotary tillage (PR), continuous no-till (CN) and ploughing-no-till (PN). The total content of nitrogen in chernozem was high during early stages of plant growth, and then it decreased with the maize growth. In the rhizosphere soil, the total N accounted 1314.45, 1265.96, 1120.47, 1120.47, 1204.05 mg·kg−1 of CR, PR, CN, and PN, respectively, which were markedly greater than that of non-rhizosphere soil (1237.52, 1168.40, 984.51, 1106.49 mg·kg−1 of CR, PR, CN, and PN, respectively). At first growth stages, content of NH4+-N and NO3−-N in two soil regions was low, then increased gradually, which followed the order of CR < PR < PN < CN. The rhizosphere soil showed slightly higher concentration of NH4+-N and NO3−-N than non-rhizosphere. The soil enzymes were more active in the rhizosphere soil than that of non-rhizosphere during the whole maize growth stages. Due to minimal damage to the soil environment and optimal soil moisture and temperature, the urease and catalase activities were greatest in the rhizosphere for CN treatment. Therefore, CN was recommended to be used by farmers for the improvement of macronutrient availability and soil enzyme activities in the soil.
10
Qin, Jianqiao, Huarong Zhao, Ming Dai, Peng Zhao, Xi Chen, Hao Liu, and Baizhou Lu. "Speciation Distribution and Influencing Factors of Heavy Metals in Rhizosphere Soil of Miscanthus Floridulus in the Tailing Reservoir Area of Dabaoshan Iron Polymetallic Mine in Northern Guangdong." Processes 10, no. 6 (June 18, 2022): 1217. http://dx.doi.org/10.3390/pr10061217.
Анотація:
Through field investigation and experimental analysis, the forms, contents and distribution of heavy metals (Zn, Pb, Cu, Cd, Ni, Cr) in rhizosphere and non-rhizosphere soils of Miscanthus floridulus growing everywhere in Tielongwei mine pond (sample plot 1), Caoduikeng tailings pond (sample plot 2), Donghua tailings pond (sample plot 3) and Small tailings pond (sample plot 4) in Dabaoshan, Guangdong Province were studied. The results showed that the main forms and distributions of heavy metals in rhizosphere and non-rhizosphere soils are basically the same, which shows that the mineral content accounts for most of the total amount of heavy metals, while the exchange content is low. Compared with non-rhizosphere soil, the proportion of exchangeable and organic heavy metals in rhizosphere soil increased significantly, in which the proportion of organic-bound Cu increased by 53.25%, the proportion of organic-bound Cd and Pb increased by more than 17%, and the proportion of Zn increased by 5.67%. At the same time, the contents of carbonate-bound and iron manganese oxide-bound decreased. Statistical analyses showed that the morphological distribution of Zn, Pb, Cu, Cd, Ni and Cr in rhizosphere soil was closely related to soil pH value, organic matter content, plant growth and other factors. The results of this study provided a basis for the restoration of heavy metal-contaminated sites by Miscanthus.
11
Zharkova, Ekaterina K., Anna A. Vankova, Olga V. Selitskaya, Elena L. Malankina, Natalya V. Drenova, Alena D. Zhelezova, Vitaliy K. Khlyustov, et al. "Bacterial Communities of Lamiacea L. Medicinal Plants: Structural Features and Rhizosphere Effect." Microorganisms 11, no. 1 (January 12, 2023): 197. http://dx.doi.org/10.3390/microorganisms11010197.
Анотація:
Bacterial communities associated with medicinal plants are an essential part of ecosystems. The rhizosphere effect is rather important in the cultivation process. The purpose of the study was to analyze the rhizosphere effect of oregano (Origanum vulgare L.), peppermint (Mentha piperita L.), thyme (Thymus vulgaris L.), creeping thyme (Thymus serpillum L.) and sage (Salvia officinalis L.). To estimate the quantity of 16S bacteria ribosomal genes, qPCR assays were used. To compare bacterial communities’ structure of medicinal plants rhizosphere with bulk soil high-throughput sequencing of the 16S rRNA targeting variable regions V3–V4 of bacteria was carried out. The highest bacterial abundance was associated with T. vulgaris L., M. piperita L. and S. officinalis L., and the lowest was associated with the O. vulgare L. rhizosphere. Phylum Actinobacteriota was predominant in all rhizosphere samples. The maximum bacterial α-diversity was found in S. officinalis L. rhizosphere. According to bacterial β-diversity calculated by the Bray–Curtis metric, T. vulgaris L. root zone significantly differed from bulk soil. The rhizosphere effect was positive to the Myxococcota, Bacteroidota, Verrucomicrobiota, Proteobacteria and Gemmatimonadota.
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Ma, Kun, Yingcheng Wang, Xin Jin, Yangan Zhao, Huilin Yan, Haijuan Zhang, Xueli Zhou, Guangxin Lu, and Ye Deng. "Application of Organic Fertilizer Changes the Rhizosphere Microbial Communities of a Gramineous Grass on Qinghai–Tibet Plateau." Microorganisms 10, no. 6 (June 2, 2022): 1148. http://dx.doi.org/10.3390/microorganisms10061148.
Анотація:
The effects of organic fertilizer application on the soil microbial community in grassland systems have been extensively studied. However, the effects of organic fertilizers on the structure of rhizosphere microbial communities are still limited. In this study, the diversity and composition of rhizosphere microbial communities of a gramineous grass Elymus nutans under organic fertilizer treatment were studied in an artificial pasture on Qinghai–Tibet Plateau. After a growing season, the application of organic fertilizer not only increased the height and biomass of Elymus nutans, but also changed the rhizosphere microbial compositions. In particular, organic fertilizer increased the diversity of rhizosphere bacterial community and inhibited the growth of pathogenic bacteria such as Acinetobacter, but the opposite trend was observed for the diversity of fungal community. The assembly process of fungal community was changed from a stochastic process to a deterministic process, indicating that selection was strengthened. Additionally, both the infection rate of arbuscular mycorrhizal fungi (AMF) toward host plants and the development of AMF-related structures were significantly increased after the application of organic fertilizer. Our study demonstrated that the addition of organic fertilizer to artificial pasture could improve the growth of grass through the alteration of the rhizosphere microbial communities. Organic fertilizer had a greater selectivity for the bacterial and the fungal communities that enhanced the niche filtration in this community, further benefiting the yield of forages.
13
White, Laura J., Karuppaiyan Jothibasu, R. Neil Reese, Volker S. Brözel, and Senthil Subramanian. "Spatio Temporal Influence of Isoflavonoids on Bacterial Diversity in the Soybean Rhizosphere." Molecular Plant-Microbe Interactions® 28, no. 1 (January 2015): 22–29. http://dx.doi.org/10.1094/mpmi-08-14-0247-r.
Анотація:
High bacterial density and diversity near plant roots has been attributed to rhizodeposit compounds that serve as both energy sources and signal molecules. However, it is unclear if and how specific rhizodeposit compounds influence bacterial diversity. We silenced the biosynthesis of isoflavonoids, a major component of soybean rhizodeposits, using RNA interference in hairy-root composite plants, and examined changes in rhizosphere bacteriome diversity. We used successive sonication to isolate soil fractions from different rhizosphere zones at two different time points and analyzed denaturing gradient gel electrophoresis profiles of 16S ribosomal RNA gene amplicons. Extensive diversity analysis of the resulting spatio temporal profiles of soybean bacterial communities indicated that, indeed, isoflavonoids significantly influenced soybean rhizosphere bacterial diversity. Our results also suggested a temporal gradient effect of rhizodeposit isoflavonoids on the rhizosphere. However, the hairy-root transformation process itself significantly altered rhizosphere bacterial diversity, necessitating appropriate additional controls. Gene silencing in hairy-root composite plants combined with successive sonication is a useful tool to determine the spatio temporal effect of specific rhizodeposit compounds on rhizosphere microbial communities.
14
Zhang, Zhen, Lu Chang, Xiuxiu Liu, Jing Wang, Xianhong Ge, Jiasen Cheng, Jiatao Xie, et al. "Rapeseed Domestication Affects the Diversity of Rhizosphere Microbiota." Microorganisms 11, no. 3 (March 11, 2023): 724. http://dx.doi.org/10.3390/microorganisms11030724.
Анотація:
Rhizosphere microbiota is important for plant growth and health. Domestication is a process to select suitable plants to satisfy the needs of humans, which may have great impacts on the interaction between the host and its rhizosphere microbiota. Rapeseed (Brassica napus) is an important oilseed crop derived from the hybridization between Brassica rapa and Brassica oleracea ~7500 years ago. However, variations in rhizosphere microbiota along with rapeseed domestication remain poorly understood. Here, we characterized the composition and structure of the rhizosphere microbiota among diverse rapeseed accessions, including ten B. napus, two B. rapa, and three B. oleracea accessions through bacterial 16S rRNA gene sequencing. B. napus exhibited a higher Shannon index and different bacterial relative abundance compared with its wild relatives in rhizosphere microbiota. Moreover, artificial synthetic B. napus lines G3D001 and No.2127 showed significantly different rhizosphere microbiota diversity and composition from other B. napus accessions and their ancestors. The core rhizosphere microbiota of B. napus and its wild relatives was also described. FAPROTAX annotation predicted that the synthetic B. napus lines had more abundant pathways related to nitrogen metabolism, and the co-occurrence network results demonstrated that Rhodoplanes acted as hub nodes to promote nitrogen metabolism in the synthetic B. napus lines. This study provides new insights into the impacts of rapeseed domestication on the diversity and community structure of rhizosphere microbiota, which may highlight the contribution of rhizosphere microbiota to plant health.
15
Zhang, Jianfeng, Zongmu Yao, Yalin Chen, Jiafan Zhang, Shouyang Luo, Chunjie Tian, and Lei Tian. "Study of Rhizosphere Microbial Community Structures of Asian Wild and Cultivated Rice Showed That Cultivated Rice Had Decreased and Enriched Some Functional Microorganisms in the Process of Domestication." Diversity 14, no. 2 (January 20, 2022): 67. http://dx.doi.org/10.3390/d14020067.
Анотація:
Asian cultivated rice (Oryza sativa L.), domesticated from Asian wild rice, is a staple food crop for populations around the world. Asian cultivated rice has undergone physiological changes in the process of its evolution from Asian wild rice, and the closely related rhizosphere microorganisms may have changed in the process of plant domestication. However, the rhizosphere microorganisms of different Asian wild rice species and their related indica and japonica cultivated rice have not yet been illustrated clearly. This study aimed to illustrate the microbial community structures in the rhizosphere of Asian wild rice (common wild rice, nivara wild rice, medicinal wild rice, and spotted wild rice) and Asian cultivated rice (indica and japonica accessions) through the high-throughput sequencing of 16S rDNA, ITS amplifiers and metagenomic data. The results showed that there were significant differences between wild and cultivated rice in their rhizosphere microbial community structures. In view of the indica and japonica rice, the bacterial and fungal community structures of indica rice with the nivara wild rice and medicinal wild rice were more similar than the japonica rice species. The indica and japonica rice had the lowest proportion of Actinobacteria than the wild rice species, and indica rice has the highest relative abundance of Nitrospira. As for the microbial functions, methane metabolism and pyruvate metabolism were found to be the common pathway enriched in the rhizosphere of common and nivara wild rice in comparison with the indica and japonica rice; in addition, though it was found that the relative abundances of the pathogenic fungi in the rhizosphere soil of indica and japonica rice were significantly lower than that of the wild rice, the relative abundances of Magnaporthales and Ustilaginales were significantly higher in indica and japonica rice than that of the wild rice. This study is expected to provide a theoretical basis for the development and utilization of rhizosphere microbial resources for wild and cultivated rice.
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Valadares, Rafael Vasconcelos, Júlio César Lima Neves, Maurício Dutra Costa, Philip James Smethurst, Luiz Alexandre Peternelli, Guilherme Luiz Jesus, Reinaldo Bertola Cantarutti, and Ivo Ribeiro Silva. "Modeling rhizosphere carbon and nitrogen cycling in <i>Eucalyptus</i> plantation soil." Biogeosciences 15, no. 16 (August 22, 2018): 4943–54. http://dx.doi.org/10.5194/bg-15-4943-2018.
Анотація:
Abstract. Vigorous Eucalyptus plantations produce 105 to 106 km ha−1 of fine roots that probably increase carbon (C) and nitrogen (N) cycling in rhizosphere soil. However, the quantitative importance of rhizosphere priming is still unknown for most ecosystems, including these plantations. Therefore, the objective of this work was to propose and evaluate a mechanistic model for the prediction of rhizosphere C and N cycling in Eucalyptus plantations. The potential importance of the priming effect was estimated for a typical Eucalyptus plantation in Brazil. The process-based model (ForPRAN – Forest Plantation Rhizosphere Available Nitrogen) predicts the change in rhizosphere C and N cycling resulting from root growth and consists of two modules: (1) fine-root growth and (2) C and N rhizosphere cycling. The model describes a series of soil biological processes: root growth, rhizodeposition, microbial uptake, enzymatic synthesis, depolymerization of soil organic matter, microbial respiration, N mineralization, N immobilization, microbial death, microbial emigration and immigration, and soil organic matter (SOM) formation. Model performance was quantitatively and qualitatively satisfactory when compared to observed data in the literature. Input variables with the most influence on rhizosphere N mineralization were (in order of decreasing importance) root diameter > rhizosphere thickness > soil temperature > clay concentration. The priming effect in a typical Eucalyptus plantation producing 42 m3 ha−1 yr−1 of shoot biomass, with assumed losses of 40 % of total N mineralized, was estimated to be 24.6 % of plantation N demand (shoot + roots + litter). The rhizosphere cycling model should be considered for adaptation to other forestry and agricultural production models where the inclusion of such processes offers the potential for improved model performance.
17
Dwiastuti, Mutia Erti, Suharjono, Unun Triasih, Listy Anggraeni, Anang Triwiratno, Fauziah Fauziah, and Nensi Agustina. "Rhizosphere Fungi Abundance on Acid Dry and Tidal Soils in Borneo Prima Citrus Fields, East Kalimantan." E3S Web of Conferences 483 (2024): 01001. http://dx.doi.org/10.1051/e3sconf/202448301001.
Анотація:
Acid dry and Tidal land in East Kalimantan is one of the suboptimal land ecosystems, that needs to increase the quality of its fertility to support the production of citrus of the Borneo Prima variety. One of them with rhizosphere microbes can increase fertility, decomposition process and and as biological control agents to plant diseases. The aim of the study was to determine the abundance of rhizosphere fungi on citrus trees on dry acid and tidal soils and their relationship with soil physico-chemical factors. Rhizosphere fungi was isolated from the soil around citrus plant roots, East Kalimantan were analysed for their abundance and their correlation with soil physio-chemical factors. The results showed that found 29 rhizosphere fungi. The highest importance value index was found TR25 rhizosphere fungi isolates in the acid dry land block A and TR 17 in block B. The highest importance value index is at TR1 in block A tidal land, and TR23 in block B. Principal Component Analysis results showed that there is a strong relationship between the abundance of rhizosphere fungi and soil physicochemical. The highest number of rhizosphere fungal colonies was on tidal land B. The number of colonies was directly proportional to humidity.
18
Ganjar Samudro and Sarwoko Mangkoedihardjo. "Phytoreactor for Arsenic Biodetoxification: An Integrated Sequential Process of Phytoremediation Involving Multi-Kingdom Organisms." Journal of Advanced Research in Applied Sciences and Engineering Technology 36, no. 2 (December 30, 2023): 21–35. http://dx.doi.org/10.37934/araset.36.2.2135.
Анотація:
Phytoremediation of polluted environments has received attention and developed rapidly in recent decades. Plant performance assessment is conducted around the effectiveness and efficiency of reducing the concentration of pollutants and certain plant-associated organisms. While supporting these advances, this paper aims to develop integrated phytoremediation as a pollutant treatment reactor involving all processes and multi-kingdoms of organisms, referred to as phytoreactor. The data collected comes from the results of previous studies related to various kinds of phytoremediation processes. Screening and selection of data were based on criteria for differences in plant processes, involvement of various plant-associated organisms, and aesthetics. An arsenic pollutant, one of the most toxic metalloids and ubiquitous, the kingdom’s involvement of plant-associated organisms between aboveground and belowground plant parts. A new perspective in phytoremediation is creating a phytoreactor that integrates three sequential processes. Starting with the containment of toxic pollutants, followed by a primary process consisting of physicochemical and biological processes, and completed by a secondary process in plants, which produces nontoxic environmental media conditions. The primary biological processes are carried out in the rhizosphere and phyllosphere. The involvement of the plant-associated organism kingdom is different in the rhizosphere and phyllosphere due to the suitability of the habitat, the type of pollutant, and the aesthetics of the application of the phytoreactor. Phytoreactor for the remediation of polluted environments involves synergistic multi-kingdoms of plant-associated organisms for specific types of pollutants in the rhizosphere and phyllosphere.
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Vieira, Selma, Johannes Sikorski, Sophie Dietz, Katharina Herz, Marion Schrumpf, Helge Bruelheide, Dierk Scheel, Michael W. Friedrich, and Jörg Overmann. "Drivers of the composition of active rhizosphere bacterial communities in temperate grasslands." ISME Journal 14, no. 2 (October 28, 2019): 463–75. http://dx.doi.org/10.1038/s41396-019-0543-4.
Анотація:
Abstract The active bacterial rhizobiomes and root exudate profiles of phytometers of six plant species growing in central European temperate grassland communities were investigated in three regions located up to 700 km apart, across diverse edaphic conditions and along a strong land use gradient. The recruitment process from bulk soil communities was identified as the major direct driver of the composition of active rhizosphere bacterial communities. Unexpectedly, the effect of soil properties, particularly soil texture, water content, and soil type, strongly dominated over plant properties and the composition of polar root exudates of the primary metabolism. While plant species-specific selection of bacteria was minor, the RNA-based composition of active rhizosphere bacteria substantially differed between rhizosphere and bulk soil. Although other variables could additionally be responsible for the consistent enrichment of particular bacteria in the rhizosphere, distinct bacterial OTUs were linked to the presence of specific polar root exudates independent of individual plant species. Our study also identified numerous previously unknown taxa that are correlated with rhizosphere dynamics and hence represent suitable targets for future manipulations of the plant rhizobiome.
20
Honchar, A. N., O. L. Tonkha, N. V. Patyka, and O. S. Makarchuk. "Peculiarities of change in number and composition of winter wheat rhizosphere microbiome in the process of ontogenesis." PLANT AND SOIL SCIENCE 12, no. 3 (2021): 56–65. http://dx.doi.org/10.31548/agr2021.03.056.
Анотація:
In agroecosystems, microorganisms are the main factor in the soil formation process, plant nutrition and phytosanitary condition of the soil. Therefore, all measures aimed at restoring soil fertility and increasing productivity, environmental safety of agricultural production are closely linked to the activities of microorganisms. Increased local activity, biomass and diversity of microbiota are one of the most important characteristics that distinguish the rhizosphere from the total soil volume. The aim of the research was to study the number and composition of the microbial complex of the rhizosphere of cereals (winter wheat of different varieties of domestic selection) in the process of ontogenesis. To conduct a set of microbiological studies, soil samples were taken and prepared (typical chernozem) in compliance with the standard requirements for sample preparation and storage of samples in the laboratory. The analysis of rhizosphere soil samples was performed according to the variants of different varieties of winter wheat of domestic selection. The number of soil microorganisms was determined by the method of inoculation of suspensions on nutrient media according to generally accepted methods in microbiology. Determination of the total microbial biomass in the soil was carried out by the rehydration method, and the intensity of "respiration" of the soil, respectively, by the release of CO2 and O2 absorption by the manometric method (Warburg apparatus). It is established that varietal specificity is significantly related to the peculiarities of microbiome formation in different phases of plant growth and development, which is an integral indicator of functional and metabolic activity of soil microorganisms. The number and composition of the microbial complex of winter wheat rhizosphere in the process of ontogenesis changes significantly, especially in the ratio of the number of spore-forming and non-spore forms of microorganisms under the same conditions of crop cultivation. The total pool of saprotrophic microorganisms of the rhizosphere demonstrates the variability of biomass and changes in favor of ecoplastic Bacillus. An increase in the number of spore-forming bacteria to 4.2 x 107 CFU/g in the variants of growing certain varieties was found. It is shown that in the cultivation of different varieties of winter wheat there are stable indicators of the intensity of CO2 emissions - from 5.2 to 7.0. A similar trend can be traced to the absorption of O2 (not more than 5.3-6.8).
21
Delorme, T. A., J. V. Gagliardi, J. S. Angle, and R. L. Chaney. "Influence of the zinc hyperaccumulatorThlaspi caerulescensJ. & C. Presl. and the nonmetal accumulatorTrifolium pratenseL. on soil microbial populations." Canadian Journal of Microbiology 47, no. 8 (August 1, 2001): 773–76. http://dx.doi.org/10.1139/w01-067.
Анотація:
Metal hyperaccumulator plants like Thlaspi caerulescens J. & C. Presl. are used for phytoremediation of contaminated soils. Since little is known about the rhizosphere of hyperaccumulators, the influence of T. caerulescens was compared with the effects of Trifolium pratense L. on soil microbes. High- and low-metal soils were collected near a zinc smelter in Palmerton, Penn. Soil pH was adjusted to 5.8 and 6.8 by the addition of Ca(OH)2. Liming increased bacterial populations and decreased metal toxicity to levels allowing growth of both plants. The effects of the plants on total (culturable) bacteria, total fungi, as well as cadmium- and zinc-resistant populations were assessed in nonrhizosphere and rhizosphere soil. Both plants increased microbial populations in rhizosphere soil compared with nonrhizosphere soil. Microbial populations were higher in soils planted with T. pratense, but higher ratios of metal-resistant bacteria were found in the presence of T. caerulescens. We hypothesize that T. caerulescens acidifies its rhizosphere. Soil acidification in the rhizosphere of T. caerulescens would affect metal uptake by increasing available metals around the roots and consequently, increase the selection for metal-resistant bacteria. Soil acidification may be part of the hyperaccumulation process enhancing metal uptake from soil.Key words: phytoremediation, Thlaspi caerulescens J. & C. Presl., Trifolium pratense L., rhizosphere, soil microbial populations.
22
Tokmakova, L. M., A. O. Trepach, and I. V. Larchenko. "ACTION OF PHOSPHATE-MOBILIZING BACTERIA AGROBACTERIUM RADIOBACTER ON THE PHOSPHATASE ACTIVITY IN THE RHIZOSPHERE SOIL OF WINTER WHEAT PLANTS." Agriciltural microbiology 26 (October 27, 2017): 37–41. http://dx.doi.org/10.35868/1997-3004.26.37-41.
Анотація:
Phosphatase activity in rhizosphere soil of winter wheat plants variety Poliska 90 under the actionof phosphate-mobilizing bacteria Agrobacterium radiobacter has been investigated in a field experimenton leached chernozem. It was found, that bacterization of seeds of winter wheat with A. radiobactercontributes to improved phosphatase activity in rhizosphere soil that probably promotes activation ofmineralization process of organic phosphorus compounds in the soil and improves phosphorus nutritionof plants.
23
Cheng, Zhiqiang, Shaonan Lei, Ye Li, Wei Huang, Rongqin Ma, Juan Xiong, Ting Zhang, et al. "Revealing the Variation and Stability of Bacterial Communities in Tomato Rhizosphere Microbiota." Microorganisms 8, no. 2 (January 25, 2020): 170. http://dx.doi.org/10.3390/microorganisms8020170.
Анотація:
Microorganisms that colonize the plant rhizosphere can contribute to plant health, growth and productivity. Although the importance of the rhizosphere microbiome is known, we know little about the underlying mechanisms that drive microbiome assembly and composition. In this study, the variation, assembly and composition of rhizobacterial communities in 11 tomato cultivars, combined with one cultivar in seven different sources of soil and growing substrate, were systematically investigated. The tomato rhizosphere microbiota was dominated by bacteria from the phyla Proteobacteria, Bacteroidetes, and Acidobacteria, mainly comprising Rhizobiales, Xanthomonadales, Burkholderiales, Nitrosomonadales, Myxococcales, Sphingobacteriales, Cytophagales and Acidobacteria subgroups. The bacterial community in the rhizosphere microbiota of the samples in the cultivar experiment mostly overlapped with that of tomato cultivar MG, which was grown in five natural field soils, DM, JX, HQ, QS and XC. The results supported the hypothesis that tomato harbors largely conserved communities and compositions of rhizosphere microbiota that remains consistent in different cultivars of tomato and even in tomato cultivar grown in five natural field soils. However, significant differences in OTU richness (p < 0.0001) and bacterial diversity (p = 0.0014 < 0.01) were observed among the 7 different sources of soil and growing substrate. Two artificial commercial nutrient soils, HF and CF, resulted in a distinct tomato rhizosphere microbiota in terms of assembly and core community compared with that observed in natural field soils. PERMANOVA of beta diversity based on the combined data from the cultivar and soil experiments demonstrated that soil (growing substrate) and plant genotype (cultivar) had significant impacts on the rhizosphere microbial communities of tomato plants (soil, F = 22.29, R2 = 0.7399, p < 0.001; cultivar, F = 2.04, R2 = 0.3223, p = 0.008). Of these two factors, soil explained a larger proportion of the compositional variance in the tomato rhizosphere microbiota. The results demonstrated that the assembly process of rhizosphere bacterial communities was collectively influenced by soil, including the available bacterial sources and biochemical properties of the rhizosphere soils, and plant genotype.
24
Costa, Paulo Henrique de Oliveira, Sidney Vasconcelos do Nascimento, Hector Herrera, Markus Gastauer, Silvio Junio Ramos, Cecílio Frois Caldeira, Guilherme Oliveira, and Rafael Borges da Silva Valadares. "Non-Specific Interactions of Rhizospheric Microbial Communities Support the Establishment of Mimosa acutistipula var. ferrea in an Amazon Rehabilitating Mineland." Processes 9, no. 11 (November 19, 2021): 2079. http://dx.doi.org/10.3390/pr9112079.
Анотація:
Mimosa acutistipula var. ferrea (Fabaceae) is endemic to ferruginous tropical rocky outcrops in the eastern Amazon, also known as canga. Canga are often associated with mining activities and are the target of protection and rehabilitation projects. M. acutistipula stands out in this biodiversity hotspot with high growth rates, even in rehabilitating minelands (RMs). However, little is known about the diversity of soil microorganisms interacting with M. acutistipula in canga and RMs. This study analyzed the rhizosphere-associated bacterial and fungal microbial communities associated with M. acutistipula growing in an RM and a native shrub canga. The fungal phylum Ascomycota was the dominant taxa identified in the rhizosphere of the canga (RA: 98.1) and RM (RA: 93.1). The bacterial phyla Proteobacteria (RA: 54.3) and Acidobacteria (RA: 56.2) were the dominant taxa identified in the rhizosphere in the canga and RM, respectively. Beneficial genera such as Bradyrhizobium, Rhodoplanes, and Paraconiothyrium were identified in the rhizosphere of M. acutistipula in both areas. However, the analyses showed that the fungal and bacterial diversity differed between the rhizosphere of the canga and RM, and that the microbial taxa adapted to the canga (i.e., Rasamsonia, Scytalidium, Roseiarcus, and Rhodomicrobium) were lacking in the RM. This influences the microbe-mediated soil processes, affecting long-term rehabilitation success. The results showed that M. acutistipula established non-specific interactions with soil microorganisms, including beneficial taxa such as nitrogen-fixing bacteria, mycorrhizal fungi, and other beneficial endophytes, well known for their importance in plant adaptation and survival. High levels of microbe association and a plant’s ability to recruit a wide range of soil microorganisms help to explain M. acutistipula’s success in rehabilitating minelands.
25
Xiao, Jian, Jianglin Zhang, Yajie Gao, Yanhong Lu, Xue Xie, Changyu Fang, Yulin Liao, and Jun Nie. "Long-Term Chemical Fertilization Drove Beneficial Bacteria for Rice Soil to Move from Bulk Soil to the Rhizosphere." Agronomy 13, no. 6 (June 19, 2023): 1645. http://dx.doi.org/10.3390/agronomy13061645.
Анотація:
Overuse of chemical fertilizer (CF) causes damage to soil and the environment. To reveal the process of the response of crop rhizospheric and bulk soil fertility and the bacterial community to long-term CF conditions, CF application and nonfertilization (CK, control) treatments were used in a long-term (12-year) fertilization experiment. Long-term CF application significantly increased the soil organic matter, total nitrogen, and available phosphorus contents (p < 0.05), increased the available nitrogen (AN) and potassium (AK) contents to varying degrees, and decreased the soil pH in both rice rhizospheric soil and bulk soil. In addition, the bacterial Shannon and Ace indices in rice rhizospheric soil under the CF treatment were all higher than those under the control (CK) treatment, and the bulk soil bacteria showed the opposite trend. The LEfSe results showed that unidentified_Gammaproteobacteria and Geobacter (genera) were significantly enriched in the rhizospheric and bulk soil of rice under the CK treatment, respectively. Gemmatimonadetes (phylum) and Nitrospirae (phylum) + Thiobacillus (genus) were significantly enriched in the rice rhizospheric and bulk soil under the CF treatment. Only AK and AN had strong positive correlations with soil bacteria. Long-term CF application accelerated the migration of soil bacteria from the bulk soil to the rhizosphere, thus improving soil fertility and nutrient cycling.
26
Miller, Sarah B., Adam L. Heuberger, Corey D. Broeckling, and Courtney E. Jahn. "Non-Targeted Metabolomics Reveals Sorghum Rhizosphere-Associated Exudates are Influenced by the Belowground Interaction of Substrate and Sorghum Genotype." International Journal of Molecular Sciences 20, no. 2 (January 19, 2019): 431. http://dx.doi.org/10.3390/ijms20020431.
Анотація:
Root exudation is an important plant process by which roots release small molecules into the rhizosphere that serve in overall plant functioning. Yet, there is a major gap in our knowledge in translating plant root exudation in artificial systems (i.e., hydroponics, sterile media) to crops, specifically for soils expected in field conditions. Sorghum (Sorghum bicolor L. Moench) root exudation was determined using both ultra-performance liquid chromatography and gas chromatography mass spectrometry-based non-targeted metabolomics to evaluate variation in exudate composition of two sorghum genotypes among three substrates (sand, clay, and soil). Above and belowground plant traits were measured to determine the interaction between sorghum genotype and belowground substrate. Plant growth and quantitative exudate composition were found to vary largely by substrate. Two types of changes to rhizosphere metabolites were observed: rhizosphere-enhanced metabolites (REMs) and rhizosphere-abated metabolites (RAMs). More REMs and RAMs were detected in sand and clay substrates compared to the soil substrate. This study demonstrates that belowground substrate influences the root exudate profile in sorghum, and that two sorghum genotypes exuded metabolites at different magnitudes. However, metabolite identification remains a major bottleneck in non-targeted metabolite profiling of the rhizosphere.
27
Zhu, Yinuo, Jing Li, Zhangjie Cai, Wei Li, Yinru Lei, Manyin Zhang, and Lijuan Cui. "Relationships between nitrogen removal processes and functional microorganisms in the rhizosphere soil in a horizontal surface flow constructed wetland." Marine and Freshwater Research 70, no. 11 (2019): 1603. http://dx.doi.org/10.1071/mf19033.
Анотація:
Plant species could significantly affect the nitrogen removal processes mediated by microorganisms in constructed wetlands. However, the links between nitrogen removal processes in the rhizosphere and the related functional microorganisms in a horizontal surface flow constructed wetland in winter remain poorly understood. In this study we collected 24 rhizosphere soils from Typha orientalis and Phragmites australis to evaluate potential nitrogen removal activities, namely the potential nitrification rate (PNR) and denitrification enzyme activity (DEA), and their relationship with functional genes (i.e. nitrate reductase, nirS, and ammonia mono-oxygenase, amoA, of ammonia-oxidising archaea, AOA, and ammonia-oxidising bacteria, AOB) in denitrifiers and nitrifiers in winter. DEA and PNR were significantly higher in the rhizosphere soil of T. orientalis than P. australis, which was due to the higher abundance of nitrifiers and denitrifiers in the rhizosphere of T. orientalis. AOB were the major predictor of PNR in rhizosphere soil of T. orientalis, whereas AOA were more important for P. australis. In addition, denitrifiers containing the nirS gene were found to be the main drivers of DEA, and AOA and AOB also contributed to the denitrification process in the rhizosphere soil of both plants. Furthermore, the abundance of nitrifiers was significantly affected by the C:N ratio, soil organic matter and moisture, whereas the abundance of denitrifiers was affected by soil moisture and pH.
28
Ayangbenro, Ayansina Segun, Chinenyenwa Fortune Chukwuneme, Modupe Stella Ayilara, Funso Raphael Kutu, Motlagomang Khantsi, Bartholomew Saanu Adeleke, Bernard R. Glick, and Olubukola Oluranti Babalola. "Harnessing the Rhizosphere Soil Microbiome of Organically Amended Soil for Plant Productivity." Agronomy 12, no. 12 (December 15, 2022): 3179. http://dx.doi.org/10.3390/agronomy12123179.
Анотація:
Soil degradation remains an ongoing process that is exacerbated by the effects of climate change. Consequently, these processes decrease soil organic matter and nutrient contents, soil biological functions, and plant productivity. The addition of organic amendments (OAs) to the soil is a widespread practice to enhance soil quality and the health of agricultural soils. One of the most significant microbial hotspots controlling the processes, dynamics, and cycling of nutrients, carbon and water in terrestrial ecosystems is the rhizosphere. Understanding the continuing transformations of OAs and the distribution of different factors (C, nutrients, and microbial activities) across and along roots is crucial in the rhizosphere. The application of OAs to soil increases soil organic matter and nutrients, water holding capacity, improves soil structure and stimulates soil microbial activity and biomass. This review evaluates the role of the rhizosphere microbial community in organically amended soils for promoting plant growth and health. The diversity of the rhizosphere microbiome and the mechanisms used in plant protection are discussed.
29
Korenblum, Elisa, Yonghui Dong, Jedrzej Szymanski, Sayantan Panda, Adam Jozwiak, Hassan Massalha, Sagit Meir, Ilana Rogachev, and Asaph Aharoni. "Rhizosphere microbiome mediates systemic root metabolite exudation by root-to-root signaling." Proceedings of the National Academy of Sciences 117, no. 7 (February 3, 2020): 3874–83. http://dx.doi.org/10.1073/pnas.1912130117.
Анотація:
Microbial communities associated with roots confer specific functions to their hosts, thereby modulating plant growth, health, and productivity. Yet, seminal questions remain largely unaddressed including whether and how the rhizosphere microbiome modulates root metabolism and exudation and, consequently, how plants fine tune this complex belowground web of interactions. Here we show that, through a process termed systemically induced root exudation of metabolites (SIREM), different microbial communities induce specific systemic changes in tomato root exudation. For instance, systemic exudation of acylsugars secondary metabolites is triggered by local colonization of bacteria affiliated with the genus Bacillus. Moreover, both leaf and systemic root metabolomes and transcriptomes change according to the rhizosphere microbial community structure. Analysis of the systemic root metabolome points to glycosylated azelaic acid as a potential microbiome-induced signaling molecule that is subsequently exuded as free azelaic acid. Our results demonstrate that rhizosphere microbiome assembly drives the SIREM process at the molecular and chemical levels. It highlights a thus-far unexplored long-distance signaling phenomenon that may regulate soil conditioning.
30
Zaim, Souad, and Ahmed Amine Bekkar. "Advances in research on the use of Brevundimonas spp. to improve crop and soil fertility and for soil bioremediation." Algerian Journal of Biosciences 4, no. 1 (June 30, 2023): 045–51. http://dx.doi.org/10.57056/ajb.v4i1.109.
Анотація:
Biofertilizers or biological fertilizers maintain soil fertility by fixing atmospheric nitrogen, solubilizing P and K, producing plant growth substances and antibiotics as well as biodegradation of organic matter in the soil that enriches the root rhizosphere. Microbial biofertilizers are eco-friendly and less expensive alternatives to chemical fertilizers. The key components of healthy soil are populations of plant growth promoting rhizobacteria (PGPR) which play multiple beneficial and ecological roles in the rhizosphere soil. PGPR colonizes rhizosphere or plant roots, resulting in phytostimulation, biofertilization and biocontrol either directly and/or indirectly. Another important role of PGPR is its ability to decontaminate soils through a process called soil bioremediation. Recently, the known rhizobacteria environmentally friendly biofertilizers for sustainable agriculture are those belonging to Brevundimonas spp., which play a significant role in improving crop production and soil health
31
Khan, Naeem. "Molecular Communication between Plants and Plant-Growth-Promoting Microorganisms for Stress Tolerance." Microorganisms 10, no. 6 (May 25, 2022): 1088. http://dx.doi.org/10.3390/microorganisms10061088.
32
Manekar, Urwashi, Tirunima Patle, S. K. Sharma, and Ranjeet. "Estimation of the pH of soybean rhizoplane, rhizosphere and bulk soil and its effect on availability and uptake of phosphorus in calcareous Vertisols." INTERNATIONAL JOURNAL OF AGRICULTURAL SCIENCES 17, AAEBSSD (July 15, 2021): 229–32. http://dx.doi.org/10.15740/has/ijas/17-aaebssd/229-232.
Анотація:
Vertisols are spread over central and western parts in Madhya Pradesh in India.As the Vertisolsare calcareous and/or alkaline in nature, mobility of P from soil to root surface is carried by diffusion process, and this diffusion rate is quite low i.e. 0.13mm day-1 (Jungk 1991). One of the major limitation is thatmany rhizosphere chemical interactions that can be involved in the changes ofP ion concentration in the soil solution and in the replenishment of the depleted soil solution (P buffering capacity)do not taken into account (Darrah, 1993).This prompted us to re-evaluate the P-fertility of Vertisols. In the study an attempt has been made to evaluate the most suitable method for P availability in calcareous Vertisols for crops considering the pH of rhizosphere. By agar plate technique, the pH of rhizoplane and rhizoplane soil was found acidic even though soil pH was7.6. The major portion of inorganic P in Vertisols is associated with Ca (Ca-P), which can be soluble more under acid condition than pH 8.5 of Olsen’s condition. The pH of bulk soil, that is unplanted soil which is treated in same way of applied nutrient and water as the planted pots, is 7.9. Soybean crop decreased the pH of rhizosphere and rhizoplane by 7.5and 6.0 respectively. Following the various crops the pH of rhizosphere decreased. Among various crops tested the lowest pH (5.8) of the rhizosphere and rhizoplane -attached soil was noticed in care of Chickpea. In case of pea, maize, sorghum and wheat the pH of rhizosphere and rhizoplane were 7.4 and 6.1, 7.6 and 6.4, 7.5 and 6.4, 7.5 and 6.3, respectively. Decreased pH due to rhizosphere can dissolve the phosphorus from the Calcium and increase the availability of P in Calcareous/ Alkaline soil.
33
Bian, Fangyuan, Xiaoping Zhang, Qiaoling Li, Zhiyuan Huang, and Zheke Zhong. "Enhancement of Phytoremediation of Heavy Metal Pollution Using an Intercropping System in Moso Bamboo Forests: Characteristics of Soil Organic Matter and Bacterial Communities." Forests 14, no. 9 (September 18, 2023): 1895. http://dx.doi.org/10.3390/f14091895.
Анотація:
Heavy metal pollution in soil is a major global issue, and one effective method for addressing it is phytoremediation through bamboo planting. Nevertheless, there is a notable gap in our knowledge as no studies have explored the characteristics of soil organic matter (SOM) and the bacterial communities in bamboo forests during the remediation process. To bridge this knowledge gap, we conducted research to investigate the impact of different bamboo planting patterns on the SOM characteristics and microbial communities in soils contaminated with heavy metals. The contents of SOM and dissolved organic matter (DOM) in rhizosphere and non-rhizosphere soils differed significantly between monocropping and intercropping systems, with DOM accounting for only 1.7%–2.5% of SOM. Fourier transform infrared spectra showed that the contents of SOM polysaccharides C-O, carbonate C-O, aliphatic methyl, and methylene increased, while the aromatic C=C abundance decreased in the intercropping rhizosphere soil. The differences between bamboo cultivation patterns in the rhizosphere and non-rhizosphere soils were elucidated using the biomarkers, including MND1 and Nitrospira (non-rhizosphere), and Sphingomonas (rhizosphere). Heavy metals, DOM, SOM, and refined organic functional groups, especially C-O in polysaccharides and symmetric carboxylate, were the determining factors of soil bacterial communities. Compared to monocropping, intercropping increased the accumulation of Zn and Cd in bamboo shoots by 35% and 40%, respectively, and hence, intercropping soil, with a low toxicity, was suitable for bamboo shoot sprouting. Intercropping can alter the characteristics of SOM and bacterial communities and plays a vital role in phytoremediation and shoot growth in bamboo forests. Future studies on soil carbon dynamics and nutrient status during heavy metal remediation will improve our knowledge of soil transformation and its impact on soil ecosystem health and productivity.
34
Hendriksen, Niels Bohse, and Bjarne Munk Hansen. "Long-term survival and germination of Bacillus thuringiensis var. kurstaki in a field trial." Canadian Journal of Microbiology 48, no. 3 (March 1, 2002): 256–61. http://dx.doi.org/10.1139/w02-009.
Анотація:
Long-term survival, dispersal, and germination of Bacillus thuringiensis var. kurstaki DMU67R has been investigated in a field trial. An experimental cabbage plot was sprayed with DMU67R in 1993 and allowed to lie fallow since. The investigations reported here were carried out from 1997 to 2000 in this plot. High persistence of DMU67R for 7 years in the bulk soil of the plot has been demonstrated. The numbers have not significantly reduced since 1994, stabilizing around 6.6 × 102 cfu/g from 1996 to 2000. Horizontal dispersal of DMU67R in the 19941999 period was limited. Vertical dispersal occurred from 1994 to 1999, as 77% of the population of DMU67R occurred in the 02 cm layer in 1994, while only 22% of the population was found there in 1999. Most of the population in 1999 was present homogeneously in the upper 6 cm of the soil profile. Germination, as evidenced by the ratio of DMU67R cfu before and after heat treatment, was not observed in the bulk soil. However, in the rhizospheres of dandelion (Taraxacum officinalis) and quackgrass (Agropyron repens), 40 and 50% of DMU67R was present as vegetative germinated cells, respectively. No germination occurred in the rhizosphere of red fescue (Festuca rubra). The material from the gut of the earthworm species Lumbricus rubellus, Lumbricus terrestris, and Apporrectodea caliginosa and from a tipulid larvae from the plot also contained vegetative cells of DMU67R. Further investigations of A. caliginosa showed that germination seemed to be restricted to the gut and that sporulation occurred after defecation. The germination of DMU67R in rhizospheres and in the gut of nontarget invertebrates suggests that survival in the soil of B. thuringiensis is a dynamic process involving germination, cell divisions, and sporulation in specific microhabitats.Key words: Bacillus thuringiensis, survival, germination, dispersal, rhizosphere, earthworm.
35
Kang, An, Nan Zhang, Weibing Xun, Xiaoyan Dong, Ming Xiao, Zihao Liu, Zhihui Xu, et al. "Nitrogen fertilization modulates beneficial rhizosphere interactions through signaling effect of nitric oxide." Plant Physiology 188, no. 2 (December 1, 2021): 1129–40. http://dx.doi.org/10.1093/plphys/kiab555.
Анотація:
Abstract Chemical nitrogen (N) fertilization is customary for increasing N inputs in agroecosystems. The nutritional effects of N fertilization on plants and soil microbes have been well studied. However, the signaling effects of N fertilization on rhizosphere plant–microbe interactions and the following feedback to plant performance remain unknown. Here, we investigated the effect of different N fertilizations on the behavior of the plant growth-promoting rhizobacteria (PGPR) Bacillus velezensis SQR9 in the cucumber (Cucumis sativus L.) rhizosphere. Moderate N fertilization promoted higher rhizosphere colonization of strain SQR9 than insufficient or excessive N input. Nitric oxide (NO) produced through the denitrification process under N fertilization was identified as the signaling molecule that dominates the root colonization of PGPR, and this effect could be neutralized by the NO-specific scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxy-3-oxide. Gene expression analysis demonstrated that NO regulated the biofilm formation of strain SQR9 by affecting the synthesis of extracellular matrix γ-polyglutamic acid, consequently impacting its root colonization. Finally, we demonstrated that moderate N fertilization-modulated enhanced PGPR root colonization can significantly promote plant growth and nitrogen use efficiency. This study provides insights into our understanding of the beneficial rhizosphere plant–microbe interactions under N fertilization and suggests that rational fertilization is critical to promote beneficial rhizosphere interactions for sustainable agricultural production.
36
Guo, Jing, Zhanling Xie, Qing Meng, Hongyan Xu, Qingqing Peng, Bao Wang, Deyu Dong, Jiabao Yang, and Shunbin Jia. "Distribution of rhizosphere fungi of Kobresia humilis on the Qinghai-Tibet Plateau." PeerJ 12 (February 20, 2024): e16620. http://dx.doi.org/10.7717/peerj.16620.
Анотація:
Kobresia humilis is a major species in the alpine meadow communities of the Qinghai-Tibet Plateau (QTP); it plays a crucial role in maintaining the ecological balance of these meadows. Nevertheless, little is known about the rhizosphere fungi associated with K. humilis on the Qinghai Tibet Plateau. In this study, we used Illumina Miseq to investigate the fungal diversity, community structure, and ecological types in the root and rhizosphere soil of K. humilis across eight areas on the QTP and analyzed the correlation between rhizosphere fungi of K. humilis and environmental factors. A total of 19,423 and 25,101 operational taxonomic units (OTUs) were obtained from the roots and rhizosphere soil of K. humilis. These were classified into seven phyla, 25 classes, 68 orders, 138 families, and 316 genera in the roots, and nine phyla, 31 classes, 76 orders, 152 families, and 407 genera in the rhizosphere soil. There were 435 and 415 core OTUs identified in root and rhizosphere soil, respectively, which were categorized into 68 and 59 genera, respectively, with 25 shared genera. Among them, the genera with a relative abundance >1% included Mortierella, Microscypha, Floccularia, Cistella, Gibberella, and Pilidium. Compared with the rhizosphere soil, the roots showed five differing fungal community characteristics, as well as differences in ecological type, and in the main influencing environmental factors. First, the diversity, abundance, and total number of OTUs in the rhizosphere soil of K. humilis were higher than for the endophytic fungi in the roots by 11.85%, 9.85%, and 22.62%, respectively. The composition and diversity of fungal communities also differed between the eight areas. Second, although saprotroph-symbiotrophs were the main ecological types in both roots and rhizosphere soil; there were 62.62% fewer pathotrophs in roots compared to the rhizosphere soil. Thirdly, at the higher altitude sites (3,900–4,410 m), the proportion of pathotroph fungi in K. humilis was found to be lower than at the lower altitude sites (3,200–3,690 m). Fourthly, metacommunity-scale network analysis showed that during the long-term evolutionary process, ZK (EICZK = 1) and HY (EICHY = 1) were critical sites for development of the fungal community structure in the roots and rhizosphere soil of K. humilis, respectively. Fifthly, canonical correspondence analysis (CCA) showed that key driving factors in relation to the fungal community were longitude (R2 = 0.5410) for the root community and pH (R2 = 0.5226) for the rhizosphere soil community. In summary, these results show that K. humilis fungal communities are significantly different in the root and rhizosphere soil and at the eight areas investigated, indicating that roots select for specific microorganisms in the soil. This is the first time that the fungal distribution of K. humilis on the QTP in relation to long-term evolutionary processes has been investigated. These findings are critical for determining the effects of environmental variables on K. humilis fungal communities and could be valuable when developing guidance for ecological restoration and sustainable utilization of the biological resources of the QTP.
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Kopylov, Ye, and A. Yovenko. "Nitrogen-fixing microbial grouping of the root zone and buckwheat productivity under the influence of fungus Chaetomium cochliodes." Agroecological journal, no. 3 (September 30, 2016): 125–30. http://dx.doi.org/10.33730/2077-4893.3.2016.248885.
Анотація:
It was established that treatment of buckwheat seeds with soil saprotroph mould Chaetomium cochliodes 3250 contributes to increase the number of N2-fixing bacteria in cropsroot zone. Thus, the number of Azospirillum and Azotobacter cell was getting more in rhizosphere soil. The number of all studied ecological-trophic bacteria groups was getting more on the root surface simultaneously with N2-fixation process intensification. Nitrogenase activity had grown in 1.3 times in rhizosphere soil and in 11.3 times on the root surface.The mold usage seemed to be positive to rise up the buckwheat harvest by 12.6%.
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Kato-Noguchi, Hisashi, and Denny Kurniadie. "Allelopathy of Lantana camara as an Invasive Plant." Plants 10, no. 5 (May 20, 2021): 1028. http://dx.doi.org/10.3390/plants10051028.
Анотація:
Lantana camara L. (Verbenaceae) is native to tropical America and has been introduced into many other countries as an ornamental and hedge plant. The species has been spreading quickly and has naturalized in more than 60 countries as an invasive noxious weed. It is considered to be one of the world’s 100 worst alien species. L. camara often forms dense monospecies stands through the interruption of the regeneration process of indigenous plant species. Allelopathy of L. camara has been reported to play a crucial role in its invasiveness. The extracts, essential oil, leachates, residues, and rhizosphere soil of L. camara suppressed the germination and growth of other plant species. Several allelochemicals, such as phenolic compounds, sesquiterpenes, triterpenes, and a flavonoid, were identified in the extracts, essential oil, residues, and rhizosphere soil of L. camara. The evidence also suggests that some of those allelochemicals in L. camara are probably released into the rhizosphere soil under the canopy and neighboring environments during the decomposition process of the residues and as leachates and volatile compounds from living plant parts of L. camara. The released allelochemicals may suppress the regeneration process of indigenous plant species by decreasing their germination and seedling growth and increasing their mortality. Therefore, the allelopathic property of L. camara may support its invasive potential and formation of dense monospecies stands.
39
Otte, M. L., I. M. J. Dekkers, J. Rozema, and R. A. Broekman. "Uptake of arsenic by Aster tripolium in relation to rhizosphere oxidation." Canadian Journal of Botany 69, no. 12 (December 1, 1991): 2670–77. http://dx.doi.org/10.1139/b91-335.
Анотація:
Arsenic present in salt marsh soil is taken up by plants and subsequently transferred to other parts of the ecosystem. The reduced state of the bulk soil of salt marshes favours the mobility of arsenic. In the rhizosphere of plants however, arsenic may be immobilized owing to oxidation of arsenic (III) to less mobile arsenic (V) and adsorption to iron (hydr-)oxides. In a field survey iron concentrations in the vicinity of roots of Aster tripolium were higher than in the bulk soil. In a greenhouse experiment accumulation of arsenic and iron in the rhizosphere occurred, which could be due to the oxidizing activity of plant roots and (or) microorganisms. This process stimulates uptake of arsenic by salt marsh plants. The formation of an iron plaque seems to play an important role in the uptake of arsenic by salt marsh plants, as was indicated by an incubation experiment with root parts of A. tripolium. The results of the experiments indicate that iron plays a key factor in determining the mobility of arsenic in salt marsh soils and in the uptake and translocation processes in the plants. Although oxidation processes in the rhizosphere enhance uptake of arsenic, it may be an important detoxification mechanism for the plants. Key words: arsenic, Aster tripolium, iron, rhizosphere, salt marsh.
40
Zhang, Xu, Jinxin Peng, Xiaodong Hao, Guifang Feng, Yanhui Shen, Guanghui Wang, and Zhiqun Chen. "Serratia marcescens LYGN1 Reforms the Rhizosphere Microbial Community and Promotes Cucumber and Pepper Growth in Plug Seedling Cultivation." Plants 13, no. 5 (February 22, 2024): 592. http://dx.doi.org/10.3390/plants13050592.
Анотація:
The vegetable plug seedling plays an important role in improving vegetable production. The process of plug seedling contributes to high-quality vegetable seedlings. The substrate composition and chemical fertilizer are widely studied to promote seedling growth. However, little is known about the effect of beneficial bacteria in the rhizosphere microbial community and vegetables’ growth during plug seedling. The use of beneficial microbes to promote vegetable seedling growth is of great potential. In this study, we showed that the Serratia marcescens strain LYGN1 enhanced the growth of cucumber and pepper seedlings in plug seedling cultivation. The treatment with LYGN1 significantly increased the biomass and the growth-related index of cucumber and pepper, improving the seedling quality index. Specifically, LYGN1 also improved the cucumber and pepper root system architecture and increased the root diameter. We applied high-throughput sequencing to analyze the microbial community of the seedlings’ rhizosphere, which showed LYGN1 to significantly change the composition and structure of the cucumber and pepper rhizosphere microbial communities. The correlation analysis showed that the Abditibacteriota and Bdellovibrionota had positive effects on seedling growth. The findings of this study provide evidence for the effects of Serratia marcescens LYGN1 on the cucumber and pepper rhizosphere microbial communities, which also promoted seedling quality in plug seedling cultivation.
41
Yang, Zhiyuan, Jiayi Xu, Junlin Li, Lirong He, Hongwei Xu, Xinrong Guo, Sha Xue, and Yang Cao. "Stochastic Processes Shape Bacterial Community Diversity Patterns along Plant Niche Gradients." Agronomy 14, no. 1 (January 17, 2024): 204. http://dx.doi.org/10.3390/agronomy14010204.
Анотація:
The ecological niche gradient is an important determinant of microbial community structure. In this paper, we studied variation in rhizosphere bacterial diversity and community composition along an ecological niche gradient. We used the high-throughput sequencing of 16S rRNA genes to study changes in the rhizosphere soil microbial communities of six grass and four shrub species during the secondary succession of abandoned farmland on the Loess Plateau of China. A structural equation model (SEM) was employed to disentangle the relative contribution of ecological niche and soil properties to bacterial diversity and community composition. Proteobacteria, Acidobacteria, and Actinobacteria were the dominant phyla of rhizosphere bacteria in all samples. During the dynamics of the plant niche from low to high, bacterial community composition transitioned from Actinobacteria + Acidobacteria to Proteobacteria + Bacteroidetes higher abundance. Moreover, the bacterial diversity and species richness changed with an increasing niche gradient, showing a clear differentiation in the rhizosphere bacterial community of grassland and shrubland. Further, diversity and species richness decreased from the middle niche of B. ischaemum to the poles, indicating that the succession process had not yet reached the climax community stage. Community assembly analysis suggested that the stochastic process gradually strengthened along the increasing ecological niche gradient, especially the drift effect. Furthermore, SEM analysis showed that the ecological niche had significant negative effects on soil properties and bacterial richness, while the effects on bacterial diversity and the stochastic processes of community assembly were weakened and insignificant. Altogether, our findings suggest that the complex interaction of the ecological niche with bacterial diversity and composition was determined by soil properties. Further, bacterial diversity was not necessarily higher with increasing ecological niche gradients.
42
Zhao, Zhong, Liuyong Pang, Zhanping Zhao, and Chengguang Luo. "Impulsive State Feedback Control of the Rhizosphere Microbial Degradation in the Wetland Plant." Discrete Dynamics in Nature and Society 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/612354.
Анотація:
The rhizosphere microbe plays an important role in removing the pollutant generated from industrial and agricultural production. To investigate the dynamics of the microbial degradation, a nonlinear mathematical model of the rhizosphere microbial degradation is proposed based on impulsive state feedback control. The sufficient conditions for existence of the positive order-1 or order-2 periodic solution are obtained by using the geometrical theory of the semicontinuous dynamical system. We show the impulsive control system tends to an order-1 periodic solution or order-2 periodic solution if the control measures are achieved during the process of the microbial degradation. Furthermore, mathematical results are justified by some numerical simulations.
43
Xing, Jing, Wenqiang Fan, Jiani Wang, and Fengling Shi. "Variety-Driven Effect of Rhizosphere Microbial-Specific Recruitment on Drought Tolerance of Medicago ruthenica (L.)." Microorganisms 11, no. 12 (November 24, 2023): 2851. http://dx.doi.org/10.3390/microorganisms11122851.
Анотація:
As one of the environmental factors that seriously affect plant growth and crop production, drought requires an efficient but environmentally neutral approach to mitigate its harm to plants. Soil microbiomes can interact with plants and soil to improve the adverse effects of drought. Medicago ruthenica (L.) is an excellent legume forage with strong drought tolerance, but the key role of microbes in fighting drought stress remains unclear. What kind of flora plays a key role? Is the recruitment of such flora related to its genotype? Therefore, we selected three varieties of M. ruthenica (L.) for drought treatment, analyzed their growth and development as well as their physiological and biochemical characteristics, and performed 16S rRNA high-throughput sequencing analysis on their rhizosphere soils to clarify the variety-mediated response of rhizosphere bacteria to drought stress. It was found that among the three varieties of M. ruthenica (L.), Mengnong No.2, Mengnong No.1 and Zhilixing were subjected to drought stress and showed a reduction in plant height increment of 24.86%, 34.37%, and 31.97% and in fresh weight of 39.19%, 50.22%, and 41.12%, respectively, whereas dry weight was reduced by 23.26%, 26.10%, and 24.49%, respectively. At the same time, we found that the rhizosphere microbial community of Mengnong No. 2 was also less affected by drought, and it was able to maintain the diversity of rhizosphere soil microflora stable after drought stress, while Mennong No. 1 and Zhilixing were affected by drought stress, resulting in a decrease in rhizosphere soil bacterial community diversity indices to 92.92% and 82.27%, respectively. Moreover, the rhizosphere of Mengnon No. 2 was enriched with more nitrogen-fixing bacteria Rhizobium than the other two varieties of M. ruthenica (L.), which made it still have a good ability to accumulate aboveground biomass after drought stress. In conclusion, this study proves that the enrichment process of bacteria is closely related to plant genotype, and different varieties enrich different types of bacteria in the rhizosphere to help them adapt to drought stress, and the respective effects are quite different. Our results provide new evidence for the study of bacteria to improve the tolerance of plants to drought stress and lay a foundation for the screening and study mechanism of drought-tolerant bacteria in the future.
44
Kalinitchenko, Valery Petrovich, Alexey Pavlovich Glinushkin, Vladimir Konstantinovich Sharshak, Evgene Panteleimonovich Ladan, Tatiana Mikhailovna Minkina, Svetlana Nikolaevna Sushkova, Saglara Sergeevna Mandzhieva, et al. "Intra-Soil Milling for Stable Evolution and High Productivity of Kastanozem Soil." Processes 9, no. 8 (July 28, 2021): 1302. http://dx.doi.org/10.3390/pr9081302.
Анотація:
The long-term field experiment on the Kastanozem showed that the standard moldboard plowing to a depth of 22 cm (control), chiseling to a depth of 35 cm, and three-tier plowing (machine type PTN–40) to a depth of 45 cm was incapable of providing a stable soil structure and aggregate system. The transcendental Biogeosystem Technique (BGT*) methodology for intra-soil milling of the 20–45 cm layer and the intra-soil milling PMS–70 machine were developed. The PMS–70 soil processing provided the content of 1–3 mm sized aggregate particle fraction in the illuvial horizon of about 50 to 60%, which was 3-fold higher compared to standard plowing systems. Soil bulk density reduced in the layer 20–40 cm to 1.35 t m−3 compared to 1.51 t m−3 in the control option. In the control, the rhizosphere developed only in the soil upper layer. There were 1.3 roots per cm2 in 0–20 cm, and 0.2 roots per cm2 in 20–40 cm. The rhizosphere spreads only through the soil crevices after chilling. After three-tier plowing (PTN–40), the rhizosphere developed better in the local comfort zones of the soil profile between soil blocks impermeable for roots. After intra-soil milling PMS–70, the rhizosphere developed uniformly in the whole soil profile: 2.2 roots per cm2 in 0–20 cm; 1.7 roots per cm2 in 20–40 cm. Matric water potential was higher, soil salinization was lower, and the pH was close to neutral. Soil organic matter (SOM) content increased to 3.3% in 0–20 cm and 2.1% in 20–40 cm compared to the control (2.0% in the 0–20 cm soil layer and 1.3% in the 20–40 cm layer). The spring barley yield was 53% higher compared to the control. The technology life cycle profitability was moldboard 21.5%, chiseling 6.9%, three-tier 15.6%, and intra-soil milling 45.6%. The new design of the intra-soil milling machine provides five times less traction resistance and 80% increased reliability, halving energy costs.
45
Tian, Lixin, Yuchuan Zhang, Liyuan Zhang, Lei Zhang, Xiaoli Gao, and Baili Feng. "Biogeographic Pattern and Network of Rhizosphere Fungal and Bacterial Communities in Panicum miliaceum Fields: Roles of Abundant and Rare Taxa." Microorganisms 11, no. 1 (January 4, 2023): 134. http://dx.doi.org/10.3390/microorganisms11010134.
Анотація:
Unraveling how microbial interactions and assembly process regulate the rhizosphere abundant and rare taxa is crucial for determining how species diversity affects rhizosphere microbiological functions. We assessed the rare and abundant taxa of rhizosphere fungal and bacterial communities in proso millet agroecosystems to explore their biogeographic patterns and co-occurrence patterns based on a regional scale. The taxonomic composition was significantly distinct between the fungal and bacterial abundant and rare taxa. Additionally, the rare taxa of bacteria and fungi exhibited higher diversity and stronger phylogenetic clustering than those of the abundant ones. The phylogenetic turnover rate of abundant taxa of bacteria was smaller than that of rare ones, whereas that of fungi had the opposite trend. Environmental variables, particularly mean annual temperature (MAT) and soil pH, were the crucial factors of community structure in the rare and abundant taxa. Furthermore, a deterministic process was relatively more important in governing the assembly of abundant and rare taxa. Our network analysis suggested that rare taxa of fungi and bacteria were located at the core of maintaining ecosystem functions. Interestingly, MAT and pH were also the important drivers controlling the main modules of abundant and rare taxa. Altogether, these observations revealed that rare and abundant taxa of fungal and bacterial communities showed obvious differences in biogeographic distribution, which were based on the dynamic interactions between assembly processes and co-occurrence networks.
46
Yu, Xiaoli, Qichao Tu, Jihua Liu, Yisheng Peng, Cheng Wang, Fanshu Xiao, Yingli Lian, et al. "Environmental selection and evolutionary process jointly shape genomic and functional profiles of mangrove rhizosphere microbiomes." mLife, September 3, 2023. http://dx.doi.org/10.1002/mlf2.12077.
Анотація:
AbstractMangrove reforestation with introduced species has been an important strategy to restore mangrove ecosystem functioning. However, how such activities affect microbially driven methane (CH4), nitrogen (N), and sulfur (S) cycling of rhizosphere microbiomes remains unclear. To understand the effect of environmental selection and the evolutionary process on microbially driven biogeochemical cycles in native and introduced mangrove rhizospheres, we analyzed key genomic and functional profiles of rhizosphere microbiomes from native and introduced mangrove species by metagenome sequencing technologies. Compared with the native mangrove (Kandelia obovata, KO), the introduced mangrove (Sonneratia apetala, SA) rhizosphere microbiome had significantly (p < 0.05) higher average genome size (AGS) (5.8 vs. 5.5 Mb), average 16S ribosomal RNA gene copy number (3.5 vs. 3.1), relative abundances of mobile genetic elements, and functional diversity in terms of the Shannon index (7.88 vs. 7.84) but lower functional potentials involved in CH4 cycling (e.g., mcrABCDG and pmoABC), N2 fixation (nifHDK), and inorganic S cycling (dsrAB, dsrC, dsrMKJOP, soxB, sqr, and fccAB). Similar results were also observed from the recovered Proteobacterial metagenome‐assembled genomes with a higher AGS and distinct functions in the introduced mangrove rhizosphere. Additionally, salinity and ammonium were identified as the main environmental drivers of functional profiles of mangrove rhizosphere microbiomes through deterministic processes. This study advances our understanding of microbially mediated biogeochemical cycling of CH4, N, and S in the mangrove rhizosphere and provides novel insights into the influence of environmental selection and evolutionary processes on ecosystem functions, which has important implications for future mangrove reforestation.
47
Jiang, Miao, Fan Ye, Fulai Liu, Marian Brestic, and Xiangnan Li. "Rhizosphere melatonin application reprograms nitrogen-cycling related microorganisms to modulate low temperature response in barley." Frontiers in Plant Science 13 (October 6, 2022). http://dx.doi.org/10.3389/fpls.2022.998861.
Анотація:
Rhizospheric melatonin application has a positive effect on the tolerance of plants to low temperature; however, it remains unknown whether the rhizosphere microorganisms are involved in this process. The aim of this study was to investigate the effect of exogenous melatonin on the diversity and functioning of fungi and bacteria in rhizosphere of barley under low temperature. The results showed that rhizospheric melatonin application positively regulated the photosynthetic carbon assimilation and redox homeostasis in barley in response to low temperature. These effects might be associated with an altered diversity of microbial community in rhizosphere, especially the species and relative abundance of nitrogen cycling related microorganisms, as exemplified by the changes in rhizosphere metabolites in the pathways of amino acid synthesis and metabolism. Collectively, it was suggested that the altered rhizospheric microbial status upon melatonin application was associated with the response of barley to low temperature. This suggested that the melatonin induced microbial changes should be considered for its application in the crop cold-resistant cultivation.
48
Zboralski, Antoine, Adrien Biessy, Marie-Claude Savoie, Amy Novinscak, and Martin Filion. "Metabolic and Genomic Traits of Phytobeneficial Phenazine-Producing Pseudomonas spp. Are Linked to Rhizosphere Colonization in Arabidopsis thaliana and Solanum tuberosum." Applied and Environmental Microbiology 86, no. 4 (December 6, 2019). http://dx.doi.org/10.1128/aem.02443-19.
Анотація:
ABSTRACT Bacterial rhizosphere colonization is critical for phytobeneficial rhizobacteria such as phenazine-producing Pseudomonas spp. To better understand this colonization process, potential metabolic and genomic determinants required for rhizosphere colonization were identified using a collection of 60 phenazine-producing Pseudomonas strains isolated from multiple plant species and representative of the worldwide diversity. Arabidopsis thaliana and Solanum tuberosum (potato) were used as host plants. Bacterial rhizosphere colonization was measured by quantitative PCR using a newly designed primer pair and TaqMan probe targeting a conserved region of the phenazine biosynthetic operon. The metabolic abilities of the strains were assessed on 758 substrates using Biolog phenotype microarray technology. These data, along with available genomic sequences for all strains, were analyzed in light of rhizosphere colonization. Strains belonging to the P. chlororaphis subgroup colonized the rhizospheres of both plants more efficiently than strains belonging to the P. fluorescens subgroup. Metabolic results indicated that the ability to use amines and amino acids was associated with an increase in rhizosphere colonization capability in A. thaliana and/or in S. tuberosum. The presence of multiple genetic determinants in the genomes of the different strains involved in catabolic pathways and plant-microbe and microbe-microbe interactions correlated with increased or decreased rhizosphere colonization capabilities in both plants. These results suggest that the metabolic and genomic traits found in different phenazine-producing Pseudomonas strains reflect their rhizosphere competence in A. thaliana and S. tuberosum. Interestingly, most of these traits are associated with similar rhizosphere colonizing capabilities in both plant species. IMPORTANCE Rhizosphere colonization is crucial for plant growth promotion and biocontrol by antibiotic-producing Pseudomonas spp. This colonization process relies on different bacterial determinants which partly remain to be uncovered. In this study, we combined a metabolic and a genomic approach to decipher new rhizosphere colonization determinants which could improve our understanding of this process in Pseudomonas spp. Using 60 distinct strains of phenazine-producing Pseudomonas spp., we show that rhizosphere colonization abilities correlated with both metabolic and genomic traits when these bacteria were inoculated on two distant plants, Arabidopsis thaliana and Solanum tuberosum. Key metabolic and genomic determinants presumably required for efficient colonization of both plant species were identified. Upon further validation, these targets could lead to the development of simple screening tests to rapidly identify efficient rhizosphere colonizers.
49
Li, Jun, Feng Meng, Maibo Jiang, Hanjie Zhang, Guixin Chu, and Rui Tao. "Assembly and co-occurrence patterns of rhizosphere bacterial communities are closely linked to soil fertility during continuous cropping of cut chrysanthemum (Chrysanthemum morifolium Ramat.)." Journal of Applied Microbiology, August 3, 2023. http://dx.doi.org/10.1093/jambio/lxad175.
Анотація:
Abstract Aims Continuous cropping is known to have profound effects on the soil microbial community in different planting systems. However, we lack an understanding of how different years of continuous cropping affects rhizosphere soil bacterial community co-occurrence pattern and assembly processes in the cut chrysanthemum (Chrysanthemum morifolium Ramat.) field. Methods and results We collected the soils from cut chrysanthemum rhizospheres with planting for 1 year (PY1) and continuous cropping for 6 years (CY6) and 12 years (CY12). Real-time quantitative PCR and flow cytometry (FCM) techniques were used to test the 16S rRNA gene copy number and bacterial cell count, respectively. The bacterial community structure was analysed by using high-throughput sequencing technology. The CY12 had a significantly decreased soil fertility index and rhizosphere bacterial living cell counts and gene copy numbers compared to CY6 and PY1 (P < 0.05). The rhizosphere bacterial community dissimilarity increased as the continuous cropping years increased. Three main ecological clusters (modules #1, #2 and #3) were observed in the bacterial co-occurrence network across all samples, and only the relative abundance of module #1 (enriched in the CY12) was significantly correlated with soil fertility (P < 0.05). Moreover, the rhizosphere bacterial community assembly was primarily governed by the deterministic process under 12 years of continuous cropping. Conclusions Soil fertility decline correlates with ecological network modularization and deterministic assembly process of rhizosphere bacterial community of cut chrysanthemum during continuous cropping.
50
Taylor, Madeline, Amber Newman, and Relena Ribbons. "Exploring the Rhizosphere Microbiome of Hydroponically Grown Leafy Greens." Proceedings of the Wisconsin Space Conference, October 12, 2023. http://dx.doi.org/10.17307/wsc.v1i1.367.
Анотація:
Microgreens are immature leafy vegetables that are popular for their short growing times and versatile growing conditions. Classifying the microbial communities for different microgreens can help us understand pathways to prevent diseases and promote plant growth; however, the rhizosphere microbiome of leafy greens is poorly classified. We aimed to: 1) optimize hydroponic manifold assembly to support the growth of microgreen monocultures 2) design and optimize the process for harvesting rhizospheric film for DNA analysis and 3) determine the rhizosphere microbiome composition of four microgreens – Swiss chard, lettuce, kale, and basil. We used 16S rRNA and ITS genetic markers to quantify bacterial and fungal abundance for our four microgreens. We engineered a single-level manifold holding 36 seedlings with its own growth light and water reservoir as an ideal hydroponics set-up. We developed, refined, and optimized a root scraping procedure to maximize the amount of rhizospheric film obtained from plant roots to consistently extract viable DNA. Future work should classify and explore the mechanistic role of rhizosphere microbiome in promoting plant growth.