Screening of free-living bacteria from the rhizosphere of Jute for their multiple plant growth promoting and antagonistic activity against phytopathogens

Present investigation was undertaken to screen the PGPR isolates from the rhizosphere of Jute for their plant growth promoting and antagonistic activities in the view of an alternative way to chemical fertilizer and hazardous fungicides. A total 76 isolates were isolated from different parts of northern West Bengal and screened for their antagonistic activity against Macrophomiona phaseolina. Most promising five isolates were selected for further study and screened for other plant growth promoting and lytic enzyme producing abilities. Out of these, two isolates were Gram positive and rest three Gram negative. All five isolates exhibited several plant growth promoting activities. All five isolates showed IAA and ammonia production whereas four out five showed phosphate solubilization activity. Three PGPR strains exhibited siderophore production and only one isolate showed cyanide production ability. Among the lytic enzymes, chitinase was produced by three isolates. Among them B-3 showed highest degree of chitinase production. Protease was also produced by four strains but amylase and B-1,4-glucanase activity showed by only one isolate, Act-6. Two isolates B-3 and Acti-6 showed considerable amount of antagonistic activity against three phytopathogens Macrophomina phaseolina, Fusarium oysporum, and F. semitectum suggesting that Acti-6 and B-3 showed several attributes to be the potent strains of PGPR and can be used as biofertilizer as well as biocontrol agents.