Root Endophytic Bacterium Pseudomonas fluorescens Strain REB-4 from Berseem (Trifolium alexandrinum L.) with Plant Growth Promotion and Antifungal Activities

Berseem is a highly nutritious leguminous fodder crop which is used in rotation with cereal and other fodder crops due to its beneficial effects on soil nutrients. Endophytes isolated from roots of such nutritious plants are known to promote their growth as well as that of crop it is rotated with.

In the current study, screening of berseem root endophytic bacteria (REB) was carried out. Morphologically distinct colonies were evaluated for their growth promotion traits in terms of phosphate solubilization, hormone production and enzyme synthesis. Their effect on plant growth parameters was also recorded. The in vitro antifungal activity was assayed using dual culture technique. The most efficient isolate was identified based on 16s rRNA gene sequence homology and subjected to biochemical analysis.

All the isolates exhibited plant growth promoting traits and secreted high levels of enzymes. They showed in vitro antagonistic activities against pathogenic fungi belonging to various genera which could be due to enhanced secretion of chitinase enzyme or other bioactive molecules. The most efficient isolate was found to be Gram negative and molecularly identified as Pseudomonas fluorescens which can be used for enhanced production of berseem in future.