Exploitation of Rhizobacteria for FunctionalTraits in Mungbean

摘要

The enrichment of plant rhizosphere with beneficial bacteria is a strategy that favours the production of more vigorous seedlings, which is essential for the success of legume cultivation. The aim of this study was to select rhizobacteria that are able to act as plant growth-promoting rhizobacteria (PGPR). Atotal of 17 rhizobacteria belonging to genera Bacillus (8), Pseudomonas (5) and Azotobacter (4) from mungbean rhizosphere were selected on the basis of their ability to solubilize phosphate. Theseselected rhizobacteria were further characterized for Plant Growth Promoting (PGP) traits for quantitative phosphate solubilisation, Indole Acetic Acid (IAA), organic acid production and Intrinsic antibiotic spectra (IAR), control of phytopathogen via siderophore and cellulase production and stress tolerant management by 1 -aminocyclopropane-1 -carboxylate (ACC) deaminase activity. Significantly high phosphate was solubilized by strain of Bacillus sp. B2 (9.77 mg ml~(-100)) followed by strain of Pseudomonas sp. P10 (9.14 mg ml~(-100)) and strain of Azotobacter sp. A3 (8.98 mg ml~(-100)). In the presence of L-trptophan P10, A3 and B2 were also able to produce significant high amount of IAA i.e. 55.6 ug ml~(-1),52.6 ug ml~(-1) and 50.3 ug ml~(-1) respectively and they also produced organic acid, siderophore and cellulase. Of 17 rhizobacterial isolates, 11 were found compatible with Rhizobium sp. vigna (LSMR1) in-vitro. IAR pattern revealed 52.9 % of rhizobacteria resistant to ampicillin (10 ug disc~(-1)) and chloramphenicol (25 ug disc~(-1)). ACC deaminase activity was measured by their growth in DF medium supplemented with ACC (OD 600 ranged from 0.117 to 0.432) as nitrogen (N) source. In the present investigation, rhizobacterial isolates viz, B2, P10 and A3 were found most promising for multiple activities (PGP traits, biocontrol and stress tolerant activities) and can be evaluated in-vivo for their possible role in mungbean growth and development.