Differential response of native fluorescent pseudomonads isolates in plant growth promotion and biocontrol activity in Eleusine coracana (L.) gaertn

Abstract

In the present study, different fluorescent pseudomonads isolates from agricultural soil were characterized and identified as plant growth promoting bacteria. On the basis of specific biochemical tests, 42 were confirmed as fluorescent Pseudomonas spp. Simultaneously, when all isolates were evaluated for their biocontrol traits, 21 isolates were good HCN producers, 23 isolates were siderophore producers and 28 isolates were also identified as phosphate solubilizers. Further, all the 42 isolates were evaluated for their antagonistic activity against the four major pathogens using dual culture assay viz., Sclerotium rolfsii, Rhizoctonia solani, Pyricularia grisea and Helminthosporium nodulosum, of which 10 isolates viz., UUHF Psf-4, 11, 12, 15, 17, 20, 28, 35, 40 and 41 showed maximum per cent inhibition against all the four tested pathogens. Among all the isolates, UUHF Psf-4 exhibited maximum per cent inhibition with 83.75% towards S. rolfsii, 85.00% inhibition towards R. solani, 80.00% inhibition towards P. grisea and 78.57% inhibition towards H. nodulosum, respectively. Results of plant growth-promoting (PGP) activities in finger millet, under laboratory and glass house conditions, revealed that all the 10 putative candidates were found effective in significantly increasing most of the planting value parameters (first count, germination per cent, root length, shoot length, seedling length, fresh and dry weight, vigour index I and II) under both laboratory and glass house conditions. UUHF Psf-4 was found to be best followed by UUHF Psf-15 and UUHF Psf-41 in most of the characters studied, all being superior to control.