Isolation of Plant Growth Promoting Rhizobacteria and Their Effect on Crop Plants

Abstract

Plant growth promotion by rhizobacteria is a known phenomenon, but several aspects of the newlinerhizobacteria producing the growth elements need to be explored in a way that is provides an newlinealternative for traditional practices and provides us with sustainable agricultural practices. newlineThis present study aimed to investigate the rhizosphere bacterial isolates antagonistic newlineproperty against the soil-borne fungal phytopathogen, Sclerotium rolfsii Sacc. (Athelia rolfsii newline(Curzi) Tu and Kimbrough), Fusarium oxysporum, Rhizoctonia solani. The chemical control of newlinethe disease caused by these phytopathogens is economically and environmentally newlineunsustainable, and therefore, ecofriendly bio-control agent in the form of rhizospheric newlinebacteria is gaining importance. Five isolated rhizospheric Bacillus species were assessed for newlinetheir antagonistic potential against S. rolfsii, Fusarium oxysporum, Rhizoctonia solani based newlineon three different screening methods. All five isolates strongly inhibited the growth of newlinepathogens (S. rolfsii, F. oxysporum, R. solani and Aspergillus niger). These strains were noncompatible newlinewith Trichoderma sp. (I andII), but, compatible with Trichoderma sp. (III). Among newlinethese, 100% fungal growth (S. rolfsii) inhibition by all Bacillus spp. was observed in the newlinenovel ring method, whereas in the dual culture method, the maximum growth inhibition was newline(58%) exhibited by the strain NBRC 15539 of B. atrophaeus. The antagonistic activity newlineshowed by the modified dual culture method was also relatively high, and the highest activity newline(93.7%) was shown by the strain NBRC 15539 of B. atrophaeus. Besides, the Bacillus spp. newlinewas also evaluated for their plant growth-promoting attributes and other properties such as newlinethe production of IAA, phosphate solubilization, siderophore, HCN, amylase, protease, newlinelipase, and ammonia, including their assessment for chitinase and cellulase activity. The newlineability to synthesize Indole-3-acetic acid (IAA) is widely associated with the plant growth newlinepromoting rhizobacteria (PGPR).The optimization of IAA