Fluorescent pseudomonads, acclaimed plant associated bacterial group, are well-known plant growth promoting-biocontrol
agents in rhizosphere arena. In this study, 144 fluorescent pseudomonad isolates from rhizosphere soil samples were
screened with King’s medium B supplemented with 8-hydroxyquinoline (8-HQ) chelator and comprehensively profiled for
plant growth promotion
viz., production of indole acetic acid (IAA), siderophore, ammonia, hydrogen cyanide, motility,
phosphate solubilization, root growth promotion, and biofilm forming ability, along with two known control strains of
pseudomonads. Iron and IAA regulated secondary metabolite siderophore production were investigated quantitatively. All
isolates were positive for ammonia production and motility; 46% isolates were positive for hydrogen cyanide, 44% shown
positivity for phosphate solubilization, and 40% isolates for siderophore production. Siderotyping showed production of
hydroxamate type of siderophores which are known to be more efficient biocontrol agents. All isolates stimulated root
growth to varying extent and had potentiality to form biofilms, a critical constituent for survival on different environments.
Forty-two isolates of pseudomonads showed antagonistic behavior against the deleterious fungal pathogen
Fusarium
oxysporum
(MTCC1755). Based on the above observations and statistical analysis, 11 isolates were shortlisted for further
scrutiny. The study of biogeographic correlation and secondary metabolite profiling in association with plant growth
promotion focalizes significant assessment on the behavior and antagonistic action, which probably brings out a competent
biocontrol agent in a sustainable eco-friendly dimension.
