Chitinolytic and secondary metabolite producing Pseudomonas fluorescens isolated from Solanaceae rhizosphere effective against broad spectrum fungal phytopathogens

18 Bacterial isolates were isolated from the Rhizosphere of Solanaceae family namely brinjal, capsicum, chilli and screened for the production of chitinase enzyme. Total of 10/18 isolates were the most potent chitinolytic bacterial species. Of these, 6 isolates showing zone size > 5mm were chosen for further studies. These isolates also showed varied levels of PGPR traits –siderophore, HCN, phosphate solubilisation and IAA. Dual plate assay against few selected soil borne phytopathogens- Alternaria alternata OTA36; Alternaria brassicola OCA1; Alternaria brassiceae OCA3; Collectotrichum gleosporidose OGC1 revealed broad spectrum anti-fungal activity by isolate R. The isolate R was identified as Pseudomonas fluorescens by biochemical test. Concurrent production of siderophore, IAA, HCN, phosphate solubilisation, NH3 and catalase coupled with anti-fungal activity suggests the plant growth promotion and broad spectrum biocontrol potential of this isolate. Seed bacterization of chilli seeds with Pseudomonas treatment showed 100% germination index and almost 50% reduction in disease incidence by C. gloeosporiodes OGC1 suggesting both the biocontrol and PGPR aspect of the bacteria.

Author(s): Ramyasmruthi S*, Pallavi O, Pallavi S, Tilak K and Srividya S

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