Multifaceted Rhizobacteria-Mediated Growth Augmentation in Chickpea

Abstract

Sixty-nine rhizobacteria isolated from chickpea rhizosphere were screened for their antagonistic potential against Fusarium oxysporum f. sp. ciceris under in vitro condition. Of these, 30 isolates inhibited growth of the pathogen and 13 potent antagonists were assessed for their functionality traits. Among the antagonistic traits exhibited by antagonists, production of diffusible antimetabolites insured its inhibitory effect on growth of test fungus as well as spore germination on solid media. Inhibition of fungus biomass in broth-based dual culture was revealed by 11 antagonists, while metabolic extracts of 5 isolates reduced the radial proliferation on solid media. Implication of biocidal volatiles in antagonism was demonstrated by 11 isolates; 3 produced cyanogenic volatiles, while all were ammonia producers. Investigation for hydrolytic activity demonstrated production of chitinase by 4 isolates and β-1,4-glucanase by 11, while all were protease and amylase producers. Revealing the dual potential of bioantagonists, all the isolates tested positive for IAA and salicylic acid production, 7 for siderophore production while 10 were P-solubilizers and 8 Zn-solubilizers. Under glass house condition, bacterization of chickpea seeds with potential isolate Ps14c alone and in consortium with Mesorhizobium ciceris reduced wilt incidence in pots (soil amended with F. oxysporum) to 48 and 28%, respectively, as compared to uninoculated control (74%) and also recorded appreciable increase in growth parameters. Present investigation clearly reveals the potential of rhizobacteria for use as bioinoculants.