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Hegde, Dileep, Sunith Mahantheshappa, Jayarama Reddy et Praveen Kumar Nagadesi. « Soil Microflora in Rhizosphere of Barringtonia racemosa (L.) Spreng and Rauwolfia serpentina (L.) Benth. ex Kurz from Western Ghats region of Uttara Kannada. Karnataka, India ». Saudi Journal of Pathology and Microbiology 7, no 7 (5 juillet 2022) : 254. http://dx.doi.org/10.36348/sjpm.2022.v07i07.001.
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A study was conducted for the isolation and identification of soil micro-flora in rhizosphere of B. racemosa (L.) Spreng and R. serpentine (L.) Benth. ex Kurz, trees from Western Ghats region of Uttar Kannada, Karnataka, India. Soil samples were collected from rhizosphere of B. racemosa and R. serpentine plants, during the months of February 2022. Soil microbes were isolated by using soil dilution technique. The total number of bacteria isolated from B. racemose and R. serpentinais rhizosphere is 2,666,600 and 4,461,160 per gram of soil respectively. The rhizospheric fungal isolates present in B. racemosa and R. serpentina plants is 3,281,200 and 1,946,200 per gram of soil respectively. In B. racemosa rhizosphere, the percentage contribution is Penicillium sp with 13.679%, In R. serpentine rhizosphere, the highest percentage contribution is Cladosporium sp., Trichoderma sp.with17.663% and 17.391% respectively. In rhizosphere of B. racemose, 19 different species belonging to 15 genera were isolated; among which Penicillium species is dominating over other fungal species isolated. In rhizosphere of R. serpentina, 18 different species belonging to 11 genera were observed; among which Trichoderma sp.is dominating over other fugal species isolates. The most frequently isolated fungi from the rhizosperes of B. racemosa and R. serpentine plants are Penicillium sp and Trichoderma sp.For the first time the rhizospheric micro-flora i.e., bacteria and fungi was reported from B. racemose soil sample collected from Western Ghats region of Uttara Kannada. For the first time the rhizospheric myco-flora was reported from R. serpentine soil samples collected from Western Ghats region of Uttara Kannada. All the bacteria and fungi isolated was new report to Wester Ghats region of Uttar Kannada, Karnataka, India.
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Aware, RG, AL Uparkar, PD Bhandekar, CN Tekade et Dr ED Bagde. « Population dynamics of root inhibiting and invading micro-flora in citrus rhizosphere ». International Journal of Chemical Studies 9, no 1 (1 janvier 2021) : 170–75. http://dx.doi.org/10.22271/chemi.2021.v9.i1c.11227.
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Yang, Yihu, Jun Xu, Yan Li, Yuchen He, Yuqing Yang, Dalin Liu et Caixia Wu. « Effects of Coumarin on Rhizosphere Microbiome and Metabolome of Lolium multiflorum ». Plants 12, no 5 (1 mars 2023) : 1096. http://dx.doi.org/10.3390/plants12051096.
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Rhizosphere microorganisms can help plants absorb nutrients, coordinate their growth, and improve their environmental adaptability. Coumarin can act as a signaling molecule that regulates the interaction between commensals, pathogens, and plants. In this study, we elucidate the effect of coumarin on plant root microorganisms. To provide a theoretical basis for the development of coumarin-derived compounds as biological pesticides, we determined the effect of coumarin on the root secondary metabolism and rhizosphere microbial community of annual ryegrass (Lolium multiflorum Lam.). We observed that a 200 mg/kg coumarin treatment had a negligible effect on the rhizosphere soil bacterial species of the annual ryegrass rhizosphere, though it exhibited a significant effect on the abundance of bacteria in the rhizospheric microbial community. Under coumarin-induced allelopathic stress, annual ryegrass can stimulate the colonization of beneficial flora in the root rhizosphere; however, certain pathogenic bacteria, such as Aquicella species, also multiply in large numbers in such conditions, which may be one of the main reasons for a sharp decline in the annual ryegrass biomass production. Further, metabolomics analysis revealed that the 200 mg/kg coumarin treatment triggered the accumulation of a total of 351 metabolites, of which 284 were found to be significantly upregulated, while 67 metabolites were significantly downregulated in the T200 group (treated with 200 mg/kg coumarin) compared to the CK group (control group) (p < 0.05). Further, the differentially expressed metabolites were primarily associated with 20 metabolic pathways, including phenylpropanoid biosynthesis, flavonoid biosynthesis, glutathione metabolism, etc. We found significant alterations in the phenylpropanoid biosynthesis and purine metabolism pathways (p < 0.05). In addition, there were significant differences between the rhizosphere soil bacterial community and root metabolites. Furthermore, changes in the bacterial abundance disrupted the balance of the rhizosphere micro-ecosystem and indirectly regulated the level of root metabolites. The current study paves the way towards comprehensively understanding the specific relationship between the root metabolite levels and the abundance of the rhizosphere microbial community.
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Kumar Maurya, Manoj, Ramji Singh et Ajay Tomer. « IN VITRO EVALUATION OF ANTAGONISTIC ACTIVITY OF PSEUDOMONAS FLUORESCENSAGAINST FUNGAL PATHOGEN ». Journal of Biopesticides 07, no 01 (1 juin 2014) : 43–46. http://dx.doi.org/10.57182/jbiopestic.7.1.43-46.
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ABSTRACT The present investigation was undertaken to isolate different strains of Pseudomonas fluorescens from various agroecological zones or crop’s rhizosphere like moong, brinjal, rice, chilli, mustard, chirchida and tomato. Totally eight micro flora resembling Pseudomonas fluorescens were isolatedand three isolates were confirmed as P. fluorescens (strain P.f.01, strain P.f.05 and strain P.f.07). Pseudomonas fluorescens strains P.f 07 were found most effective with the highest antagonisticactivity against three fungal pathogen and show maximum inhibition of mycelial growth of Fusariummoniliforme (65.45%), Rhizoctonia solani (68.23%), and Alternaria alternat(48.13%).
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BOROZAN, Aurica Breica, Sorina POPESCU et Oana Maria BOLDURA. « Plants Root Interference Area, A Benefit To The Microbial Community ». Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Horticulture 74, no 1 (19 mai 2017) : 1. http://dx.doi.org/10.15835/buasvmcn-hort:12302.
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Part of byproducts synthesized by plants through photosynthesis reach the ground, where create selective microenvironments for micro-flora and associations of plant - micro-organisms, which are a benefit for plant growth Setting the interference effect of the root interference area of vines and herbaceous plants and of radicular exudates from vine rhizosphere on microbial community and estimating microbial population present on the vine leaves. The biological material was represented by leaves (Fa, Fb), and soil rhizosphere (Ra, Rb) of two varieties of vines (Tamaioasa Romanian white and black / TA, TN), and from the vine roots interference area with other herbaceous plants (Ma, Mb). The soil has never been chemically treated. The microbiological study of biological samples was performed by classical and molecular methods. Overall, bacteria had a significant presence in soil samples taken from the root interference zone (Ma, Mb). Actinomycetes quantitatively dominated the root interference area of herbaceous plant with variety TA. The range of actinomycetes species and leaves microflora was reduced. In this study we have shown that significant growth of microorganisms occurs in the interference area of vine with other herbal plants as a result of the cumulative effect of radicular exudates.
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Parshad, Jagdish, Dharam Bir Yadav, Satbir Singh Punia, Kuldeep Singh et Baljeet Singh. « Assessment of soil micro flora in rice-wheat cropping system through continuous and rotational herbicide applications ». INTERNATIONAL JOURNAL OF AGRICULTURAL SCIENCES 17, no 2 (15 juin 2021) : 455–61. http://dx.doi.org/10.15740/has/ijas/17.2/455-461.
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A long term experiment was conducted at CCS Haryana Agricultural University, Regional Research Station, Uchani (Karnal), India. Assessment of fix and rotational herbicides with and without green manure on the microbial population were studied in wheat crop during 2017-18. The treatments included fix/continuous herbicide (Clodinafop) and rotational herbicide (Sulfosulfuron) to control weeds along with weed free and weedy checks. Rhizosphere samples of wheat were collected from different plots of fixed and rotational herbicides treated soil to assess the total bacterial count, phosphate solubilizing microorganisms, actinobacteria, fungi and free-living diazotrophs. Weed free and weedy check served as check (control) for total microbial populations in the soil. Initially, herbicidal application showed negative effect on the soil microbes but retain the number later on as compared to weedy check under both conditions. But the effects of the herbicides on the micro flora in soil could be nullified through green manure.
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Bulanov, Alexander G., Anton A. Shagaev, Alexey A. Belov et Nikolay S. Markvichev. « Physiological properties of resistance strain Fusarium oxysporum ». Butlerov Communications 57, no 2 (28 février 2019) : 144–50. http://dx.doi.org/10.37952/roi-jbc-01/19-57-2-144.
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Soil microorganisms have a significant effect on microbiological cenosis. Such communities are called the root micro-flora of the plant. All organisms in the microflora are divided into two groups: rhizoplane, living directly on the root system of the plant, and rhizosphere, developing in the root area of the plant. The intensive population of the root and root zones of a plant is primarily associated with the release (exosmosome) of organic substances or exudates formed during the life of the plant. The plant microflora includes not only symbiotic and commensalithic types of interaction, but also parasitic forms. Parasitic pathogens are divided into two groups: pathogenic and conditionally pathogenic. Conditionally pathogenic microorganisms are in a latent state and have an effect only when certain conditions arise for their activation and development. Such conditions may include changes in temperature, humidity, disturbance of plant homeostasis, or damage to the integument. Pathogenic microorganisms, by contrast, are always active and infect the host organism upon contact. The pathogenicity of a microorganism is a complex of traits that adversely affect the health of the plant, cause various pathologies, leading to growth inhibition and partial inhibition of the development or complete destruction of the culture. The pathogenic properties of the Fusarium oxysporum culture F201 were investigated against the cucumber culture by Atlet F1. It was shown the phytopathogenic microorganisms Fusarium oxysporum has acquired signs of resistance without lost her aggressiveness properties against a plant. Fusarium oxysporum quite comparable with the common strain.
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Tziourrou, Pavlos, et Evangelia E. Golia. « Plastics in Agricultural and Urban Soils : Interactions with Plants, Micro-Organisms, Inorganic and Organic Pollutants : An Overview of Polyethylene (PE) Litter ». Soil Systems 8, no 1 (16 février 2024) : 23. http://dx.doi.org/10.3390/soilsystems8010023.
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Over the last few decades, different types of plastics have been found in different soil types with documented or potential negative effects on the environment, the flora and fauna inhabiting the soils, and subsequently human health. This article is a global review of the consequences of the interactions of plastics with soil, plants, soil microbes, and organic or inorganic pollutants depending on land use. It focuses on the various types of polyethylene, a widely used material with a strong presence in both agricultural and urban soils. Although the chemical formula (C2H4)n remains the same in its various classifications, the chemical behavior of polyethylene in soil varies and directly depends on its density, branching, crystallinity, and relative molecular mass, resulting in many and various differences in the properties but also in the behavior of the two main forms of polyethylene, low and high density. However, beyond the chemical composition of plastics, the climatic conditions that apply in both urban and rural areas determine the degree of corrosion as well as their shape and size, also affecting the chemical reactions that directly or indirectly affect them. In agricultural soils, plants and the microbiome present mainly in the rhizosphere seem to dramatically influence the behavior of plastics, where the interaction of all these parameters leads to changes in the availability of nutrients (phosphorus and potassium), the percentage of organic matter and the nitrogen cycle. In urban soils, the increase in temperature and decrease in humidity are the main parameters that determine the adsorption of heavy metals and organic pollutants on the surface of plastics. Although the presence of plastics is considered inevitable, perhaps a more thorough study of them will lead to a reduction in the risks of pollution in urban and rural environments. This research provides a promising perspective on the potential contribution of MP PEs to the sustainable management of soil systems.
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Kumar Gupta, Sandeep. « Role of Growth-Promoting Bacteria as Biocontrol Agent Against Root Knot Nematode of Tomato ». Bioscience Biotechnology Research Communications 14, no 4 (25 décembre 2021) : 1557–63. http://dx.doi.org/10.21786/bbrc/14.4.29.
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There are significant losses which have occurred in crops due to the infestation of plant parasitic nematode which are known as hidden enemy due to their presence in rhizosphere and their infection site on the roots. Synthetic nematicidal control is an effective strategy to combat this biotic stress but an inappropriate and deficient application of chemical pesticides have an adverse effect on soil micro-flora and fauna. Due to the environmental and regulatory pressure, use of potential biocontrol agents is the new approach for nematode management by the farming community. For this study, four potential rhizobacteria from different habitats BHU1, BHU2, BHU3 and BHU4 were assessed for their antagonistic activities against Meloidogyne incognita infecting tomato plant. These were characterized on the basis of their morphological and biochemical activities. In vitro screening of bacterial isolates was conducted in a 25-microwell plate by addition of second stage juvenile (J2) of M. incognita with nematode application. Among four bacteria,, three potential antagonistic bacteria were able to kill nematode within 24 hours. Mortality percentage of J2 M. incognita observed in sterile distilled water selected bacterial isolates ranged from 23.33 to 100% in 3h to 24h periods. Moreover, all bacterial isolates except BHU2 isolate were found positive for production of extracellular enzymes like catalase, oxidase, chitinase, amylase and gelatinase which favour effective biopesticide activity of bacteria. Further selected isolates of bacteria associated with tomato have shown a great potential as biocontrol agents against root-knot nematode in tomato during pot experiment. Based on the fact stated above, the current research focused on plant growth promoting rhizobacteria based nematodes biocontrol strategies with direct and indirect mechanism of PGPR for nematode management.
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Akash, A. U., V. Ramya, G. Uma Devi, S. N. C. V. L. Pushpavalli et S. Triveni. « Antagonist activities of native rhizosphere micro-flora against groundnut stem rot pathogen, Sclerotium rolfsii Sacc. » Egyptian Journal of Biological Pest Control 32, no 1 (28 novembre 2022). http://dx.doi.org/10.1186/s41938-022-00631-6.
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Abstract Background Stem rot caused by Sclerotium rolfsii Sacc. is a major nuisance in groundnut production, causing substantial yield losses in almost all groundnut-growing areas around the world. Biological control is regarded as a sustainable choice over the currently popular management strategy i.e., chemical control, as later has a negative influence on the environment. The present study evaluated the antagonistic effect of native rhizosphere micro-flora against groundnut stem rot pathogen S. rolfsii. Results A total of 111 bacterial isolates and 9 Trichoderma isolates isolated from groundnut rhizosphere soil were evaluated for their antagonist activity against S. rolfsii in vitro. Eight isolates (seven bacterial and one Trichoderma) were chosen as prospective biocontrol candidates based on the findings of the dual culture assay. Molecular characterization of these isolates by 16S rDNA and ITS rDNA sequencing confirmed the identity of bacterial isolates as Bacillus spp. (six B. subtilis and one B. amyloliquefaciens) and fungal isolate as Trichoderma asperellum. Also, the selected seven bacterial isolates recorded favourable results for antagonism-promoting biochemical traits. Conclusion The results of the current study suggested that the native groundnut rhizosphere micro-flora can be exploited for biological control of groundnut stem rot pathogen S. rolfsii. Further research may enable the use of the isolated rhizosphere biocontrol agents as single organisms or in a consortium for sustainable management of the groundnut stem rot pathogen.
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Cui, Rufei, Gui Geng, Gang Wang, Piergiorgio Stevanato, Yinzhuang Dong, Tai Li, Lihua Yu et Yuguang Wang. « The response of sugar beet rhizosphere micro-ecological environment to continuous cropping ». Frontiers in Microbiology 13 (7 septembre 2022). http://dx.doi.org/10.3389/fmicb.2022.956785.
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Continuous cropping can lead to increased soil-borne diseases of sugar beet (Beta vulgaris L.), resulting in a reduction in its yield quality. However, our understanding of the influence of continuous cropping on sugar beet-associated microbial community is limited and their interactions remain unclear. Here, we described and analyzed microbial diversity (N = 30) from three sugar beet belowground compartments (bulk soil, rhizosphere soil, and beetroot) using 16S rRNA and ITS sequencing. The continuous cropping showed lower bacterial alpha diversity in three belowground compartments and higher fungal alpha diversity in roots compared to the non-continuous cropping. There were significant differences in fungal community composition between the two groups. Compared with non-continuous cropping, continuous cropping increased the relative abundance of potentially pathogenic fungi such as Tausonia, Gilbellulopsis, and Fusarium, but decreased the relative abundance of Olpidium. The fungal flora in the three compartments displayed different keystone taxa. Fungi were more closely related to environmental factors than bacteria. Overall, changes in microbial diversity and composition under continuous cropping were more pronounced in the fungal communities, and the results of the study could guide development strategies to mitigate continuous crop adversity.
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Du, Jiyu, Baiquan Song, Xingfan Li et Wengong Huang. « Long-Term Cultivation of Sugar Beet : Effect on Rhizosphere Micro-flora, Soil Fertility and Beet Productivity ». Sugar Tech, 16 mars 2022. http://dx.doi.org/10.1007/s12355-022-01124-4.
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Chelangat, Awa, Joseph P. Gweyi-Onyango, Nicholas K. Korir et Maina Mwangi. « Influence of Arbuscular Mycorrhizae on Callusing and root colonization of Tea (Camellia sinensis) Clones in Kenya ». Asian Soil Research Journal, 15 mars 2021, 21–26. http://dx.doi.org/10.9734/asrj/2021/v5i130098.
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Mycorrhizal fungi are a major component of the soil micro flora in many ecosystems, but usually have limited saprophytic abilities. Arbuscular mycorrhizal fungi (AMF) are an important component of soil life and soil chemistry. In soil, phosphorus may be present in relatively large amounts, but much of it is poorly available because of the very low solubility of phosphates by formation of complexes with iron, aluminum, and calcium, leading to soil solution concentrations of 10μm or less and very low mobility. Tea is a major income earner in the country, but yields are declining since high yielding tea varieties have a major problem with rooting and take so long in the nursery. The current study was initiated to investigate the role between Mycorrhizae and plants to explain rooting and growth rates during early stages of tea establishment. It was conducted at James Finlay in Kericho County, Kenya. The experiment was laid out in a Randomized Complete Block Design (RCBD) with factorial arrangements. Phosphorus treatments consisted of a standard rate of 107.66kg ha -1, two clones of the tea (S15/10 and SC 12/28) and two mycorrhizal strains (Glomus mosseae and Glomus intraradices) plus one control without mycorrhizae. Data was collected on rate of callusing, chlorophyll content and rate of root infection by mycorrhizal fungus. Application of 50kg Mycorrhizae ha-1 exhibited the highest callusing rate on clone SC 15/10 with significant differences (P≤0.05) observed on the chlorophyll content from week 1 to week 30 where the standard application of phosphorus plus 50kg Mycorrhizae ha-1 on clone S 15/10 had the highest content consistently throughout the trial. The highest frequency of mycorrhizae colonization in the rhizosphere was observed when 70kg ha-1 was added under clone SC 12/28. AMF strains are recommended for use on tea propagation in improving callusing rate and the chlorophyll content at a rate of 50kg Mycorrhizae ha-1.
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Kang, Lei, Dongmei He, Hai Wang, Guiqi Han, Hongyang Lv, Wanting Xiao, Zhanling Zhang, Zhuyun Yan et Luqi Huang. « “Breeding on Mountains” Resulted in the Reorganization of Endophytic Fungi in Asexually Propagated Plants (Ligusticum chuanxiong Hort.) ». Frontiers in Plant Science 12 (10 novembre 2021). http://dx.doi.org/10.3389/fpls.2021.740456.
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“Breeding on mountains, cultivation in dam areas” is a unique propagation method for the vegetatively propagated plant Ligusticum chuanxiong, including two transplants between the mountain and the dam area. It is well known that the environment can influence the endophytic community structure of plants. However, the change of host endophytic flora caused by transplanting in different places and its influence on asexual reproduction are still poorly understood. We carried out three cycles of cultivation experiments on L. chuanxiong and collected stem nodes (LZ), immature rhizomes (PX), medicinal rhizomes (CX), and rhizosphere. High-throughput sequencing was performed to analyze the endophytic fungi in all samples. We observed that the diversity and richness of endophytic fungi in L. chuanxiong increased as a result of transplanting cultivation from dam areas to mountains. Local transplantation caused minor changes in the endophytic fungus structure of L. chuanxiong, while remote transplantation caused significant changes. Compared with LZ after breeding in the dam area, the LZ after breeding on mountains has more abundant Gibberella, Phoma, Pericona, Paraphoma, and Neocosmospora. The regular pattern of the relative abundance of endophytic fungi is consistent with that of the fungus in the soil, while there are also some cases that the relative abundance of endophytic fungi is the opposite of that of soil fungi. In addition, there is a significant correlation among certain kinds of endophytic fungi whether in the soil or the plants. We have isolated more gibberellin-producing and auxin-producing fungi in the LZ cultivated in the mountains than that in the LZ cultivated in the dam area. The results of pot experiments showed that the three fungi isolated from LZ cultivated in mountainous areas can promote the development of shoots, stem nodes, and internodes of LZ, and increase the activity of plant peroxidase, catalase, phenylalanine ammonia lyase, and other enzymes. We can conclude that transplantation leads to the recombination of the host endophytic fungus, the more significant the difference in the environment is, the greater the reorganization caused by transplanting. Reorganization is determined by the soil environment, hosts, and the interaction of microorganisms. Remote transplantation is a crucial opportunity to reshuffle the micro-ecological structure of the asexual reproduction of plants, and regulate the growth, development, and resistance of plants, and prevent germplasm degradation caused by asexual reproduction.
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Visentin, Ivan, Leticia Frizzo Ferigolo, Giulia Russo, Paolo Korwin Krukowski, Caterina Capezzali, Danuše Tarkowská, Francesco Gresta et al. « Strigolactones promote flowering by inducing the miR319- LA - SFT module in tomato ». Proceedings of the National Academy of Sciences 121, no 19 (3 mai 2024). http://dx.doi.org/10.1073/pnas.2316371121.
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Strigolactones are a class of phytohormones with various functions in plant development, stress responses, and in the interaction with (micro)organisms in the rhizosphere. While their effects on vegetative development are well studied, little is known about their role in reproduction. We investigated the effects of genetic and chemical modification of strigolactone levels on the timing and intensity of flowering in tomato ( Solanum lycopersicum L.) and the molecular mechanisms underlying such effects. Results showed that strigolactone levels in the shoot, whether endogenous or exogenous, correlate inversely with the time of anthesis and directly with the number of flowers and the transcript levels of the florigen-encoding gene SINGLE FLOWER TRUSS ( SFT ) in the leaves. Transcript quantifications coupled with metabolite analyses demonstrated that strigolactones promote flowering in tomato by inducing the activation of the microRNA319- LANCEOLATE module in leaves. This, in turn, decreases gibberellin content and increases the transcription of SFT . Several other floral markers and morpho-anatomical features of developmental progression are induced in the apical meristems upon treatment with strigolactones, affecting floral transition and, more markedly, flower development. Thus, strigolactones promote meristem maturation and flower development via the induction of SFT both before and after floral transition, and their effects are blocked in plants expressing a miR319-resistant version of LANCEOLATE . Our study positions strigolactones in the context of the flowering regulation network in a model crop species.
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Prescott, Cindy E. « Sinks for plant surplus carbon explain several ecological phenomena ». Plant and Soil, 28 mars 2022. http://dx.doi.org/10.1007/s11104-022-05390-9.
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AbstractPlants engage in many processes and relationships that appear to be wasteful of the high-energy compounds that they produce through carbon fixation and photosynthesis. For example, living trees keep leafless tree stumps alive (i.e. respiring) and support shaded understory trees by sharing carbohydrates through root grafts or mycorrhizal fungal networks. Plants exude a diverse array of organic compounds from their roots and leaves, which support abundant rhizosphere and phyllosphere microbiomes. Some plants release substantial amounts of sugar via extra-floral nectaries, which enrich throughfall and alter lichen communities beneath the canopy. Large amounts of photosynthetically fixed carbon are transferred to root associates such as mycorrhizal fungi and N-fixing micro-organisms. Plants also respire fixed C through an alternative pathway that does not generate ATP. Rates of each of these processes appear to be highest when plants are growing under mild-to-moderate deficiencies of nutrients or water. During this stage of deficiency, aboveground plant growth is curtailed more than photosynthesis, causing leaves to produce surplus carbohydrates. Each of the above phenomena provide a sink for these surplus carbohydrates, thereby preventing feedback inhibition of photosynthesis, and perpetuating the influx of C. Because these processes incur little cost to the source plant, they need not provide a benefit beyond the removal of surplus carbohydrates.
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Rahman, Mehjebin, Sapna Mayuri Borah, Pradip Kr Borah, Popy Bora, Bidyut Kumar Sarmah, Milan Kumar Lal, Rahul Kumar Tiwari et Ravinder Kumar. « Deciphering the antimicrobial activity of multifaceted rhizospheric biocontrol agents of solanaceous crops viz., Trichoderma harzianum MC2, and Trichoderma harzianum NBG ». Frontiers in Plant Science 14 (3 mars 2023). http://dx.doi.org/10.3389/fpls.2023.1141506.
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The Solanaceae family is generally known to be the third most economically important plant taxon, but also harbors a host of plant pathogens. Diseases like wilt and fruit rot of solanaceous crops cause huge yield losses in the field as well as in storage. In the present study, eight isolates of Trichoderma spp. were obtained from rhizospheric micro-flora of three solanaceous crops: tomato, brinjal, and chili plants, and were subsequently screened for pre-eminent biocontrol activity against three fungal (Fusarium oxysporum f. sp. lycopersicum, Colletotrichum gloeosporioides, and Rhizoctonia solani) and one bacterial (Ralstonia solanacearum) pathogen. Morphological, ITS, and tef1α marker-based molecular identification revealed eight isolates were different strains of Trichoderma. Seven isolates were distinguished as T. harzianum while one was identified as T. asperellum. In vitro antagonistic and biochemical assays indicated significant biocontrol activity governed by all eight isolates. Two fungal isolates, T. harzianum MC2 and T. harzianum NBG were further evaluated to decipher their best biological control activity. Preliminary insights into the secondary metabolic profile of both isolates were retrieved by liquid chromatography-mass spectrometry (LC-MS). Further, a field experiment was conducted with the isolates T. harzianum MC2 and T. harzianum NBG which successfully resulted in suppression of bacterial wilt disease in tomato. Which possibly confer biocontrol properties to the identified isolates. The efficacy of these two strains in suppressing bacterial wilt and promoting plant growth in the tomato crop was also tested in the field. The disease incidence was significantly reduced by 47.50% and yield incremented by 54.49% in plants treated in combination with both the bioagents. The results of scanning electron microscopy were also in consensus with the in planta results. The results altogether prove that T. harzianum MC2 and T. harzianum NBG are promising microbes for their prospective use in agricultural biopesticide formulations.
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Chaudhary, Parul, Anuj Chaudhary, Pankaj Bhatt, Govind Kumar, Hina Khatoon, Alka Rani, Saurabh Kumar et Anita Sharma. « Assessment of Soil Health Indicators Under the Influence of Nanocompounds and Bacillus spp. in Field Condition ». Frontiers in Environmental Science 9 (7 janvier 2022). http://dx.doi.org/10.3389/fenvs.2021.769871.
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Agricultural yield of major crops is low due to the injudicious use of chemical fertilizers that affects soil fertility and biodiversity severely and thereby affecting plant growth. Soil health is regulated by various factors such as physicochemical properties of the soil, availability of micro/macronutrients, soil health indicator enzymes and microbial diversity which are essential for agriculture productivity. Thus, it is required to draw attention towards an eco-friendly approach that protects the beneficial microbial population of soil. Application of different bioinoculants and agriusable nanocompounds has been reported to enhance soil quality with increased nutrient status and beneficial bacterial population, but additive effects of combined treatments on soil microbial population are largely unknown. The present study investigated the impact of nanozeolite and nanochitosan along with two Bacillus spp. on rhizospheric microbial flora and indicator enzymes to signify soil health under field conditions on maize. Soil health was ascertained by evaluating physicochemical analysis; total bacterial counts including N, P, and K solubilizing bacteria; and soil health indicator enzymes like fluorescein diacetate hydrolysis, alkaline phosphatase, β-glucosidase, dehydrogenase, amylase, and arylesterase. Change in copy number of 16S rRNA as a marker gene was used to quantify the bacterial population using quantitative PCR (qPCR) in different treatments. Our study revealed that nanocompounds with Bacillus spp. significantly (p < 0.05) enhanced total microbial count (16.89%), NPK solubilizing bacteria (46%, 41.37%, and 57.14%), and the level of soil health indicator enzymes up to twofold over control after 20, 40, and 60 days of the experiment. qPCR analysis showed a higher copy number of the 16S rRNA gene in treated samples, which also indicates a positive impact on soil bacterial population. This study presents a valuable approach to improve soil quality in combined treatments of nanocompounds and bioinoculants which can be used as a good alternative to chemical fertilizers for sustainable agriculture.