In vitro screening for salinity and drought stress tolerance in plant growth promoting bacterial strains

The present study was designed to elevate the in vitro bacterial mechanisms related to the plant growth promotion and their tolerance for sodium chloride (NaCl) and polyethylene glycol (PEG) in culture media. Total nine bacterial strains were studied for both stress tolerance under varying concentration of NaCl and PEG. Out of them, three bacterial strains namely Pseudomonas simiae AU, P. koreensis AK-1 and Carnobacterium sp. SJ-5 were found tolerate to stress and further used for biochemical characterization of ACC-deaminase, IAA and Pi-solubilization activities under both stresses. All three strains were exhibited equal amount of Pisolubilization at each stress levels. The strain P. simiae AU significantly presented the highest ACC-deaminase activity (81 nmol/mg/h and 73 nmol/mg/h) and IAA activity (41.5 Hg/mL and 39.08 Hg/mL) at 0.4M NaCl and 10% PEG stress respectively

Mechanistic understanding of metabolic cross-talk between Aloe vera and native soil bacteria for growth promotion and secondary metabolites accumulation

Plants release a wealth of metabolites into the rhizosphere that can influence the composition and activity of microbial communities. These communities, in turn, can affect the growth and metabolism of the host plant. The connection between medicinal plant and its associated microbes has been suggested, yet the mechanisms underlying selection of indigenous microbes, and their biological function in medicinal plants are largely unknown. In this study, we investigated how the Aloe vera plants select its rhizosphere bacteria and examined their functional roles in relation to plant benefit. We utilized two native plant growth promoting rhizobacterial (PGPR) strains of Aloe vera: Paenibacillus sp. GLAU-BT2 and Arthrobacter sp. GLAU-BT16, as either single or consortium inoculants for plant growth experiment. We analyzed non-targeted root metabolites in the presence of both single and consortium bacterial inoculants and confirmed their exudation in the rhizosphere. The GC-MS analysis of metabolites revealed that the bacterial inoculation in Aloe vera plants amplified the abundance of flavonoids, terpenes and glucoside metabolites in the roots, which also exuded into the rhizosphere. Flavonoids were the most common prevalent metabolite group in individual and consortium inoculants, highlighting their role as key metabolites in interactions with rhizosphere microbes. In addition, the bacterial inoculants significantly increased antioxidant activity as well as total phenolic and flavonoid content in the leaves of Aloe vera. In conclusion, we propose a model of circular metabolic communication in which rhizosphere bacteria induce the production of flavonoids in plants. In turn, the plant releases some of these flavonoids into the rhizosphere to support the indigenous microbial community for its own benefit

Exploration of multitrait antagonistic microbes against Fusarium oxysporum f.sp. lycopersici

Fusarium wilt is one of the major diseases of tomato causing extensive loss of production. Exploration of agriculturally important microbes (AIMs) for management of the tomato wilt is an ecofriendly and cost effective approach. In the present study, a total 30 Trichoderma and 30 bacterial isolates were screened in the laboratory for their biocontrol activity against Fusarium oxysporum f.sp. lycopersici (FOL). Out of all the isolates tested, Trichoderma asperellum BHU P-1 and Ochrobactrum sp. BHU PB-1 were found to show maximum inhibition of FOL in dual culture assay. Both the microbes also exhibited plant growth promoting activities such as phosphate solubilisation, production of siderophore, hydrogen cyanide (HCN), indole acetic acid (IAA) and protease activity. These microbes could be evaluated further in greenhouse and field studies for their potential use in management of Fusarium wilt of tomato

Insights in Plant-Microbe Interaction Through Genomics Approach (Part II)

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Genomics of Extremophiles for Sustainable Agriculture and Biotechnological Applications (Part I)

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Genomics of Extremophiles for Sustainable Agriculture and Biotechnological Applications (Part II)

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