PGPR attributes and molecular identification of non-rhizobial Endophytes for growth enhancement of Sesbania sesban (L) Merr.

Abstract

The ongoing research explore the isolation, characterization, identification and plant growth promoting (PGP) functions of selected the plant growth promoting rhizobacteria (PGPR) isolated from the root nodules of a wild leguminous plant Sesbania sesban (L) Merr., growing in plain area of adjacent to Shivalik hill regions of Uttarakhand. 70 bacterial isolates were attained, and their efficacy was evaluated as beneficial rhizobacteria. Critiquing their morphological, physiological, biochemical properties, PGP attributes and molecular identification. The results indicated that certain isolates exhibited consistent characteristics with Rhizobia species, such as a milky white colony with a spherical convex surface on nutrient agar media and an inability to absorb red color on yeast mannitol agar w/congo red. Out of these 70 isolates 54 were found gram-positive and 16 were gram-+. Gram-negative isolates were further selected for investigation. Moreover, these isolates demonstrated remarkable tolerance to high salinity, pH, and temperature. Most promising bacteria that shows better PGP traits were identified based on 16S rRNA gene sequencing. These beneficial non-rhizobial endophytes were identified as Enterobacter xiangfangensis (SSP01) and Acinetobacter pittii (SSP03). Consortium of the isolates considered as most significant output. On the basis of pot trial results, we, harnessed the beneficial properties of these associative and symbiotic bacteria to enhance biomass accumulation and vegetative growth parameters in S. sesban. This study may contribute to eco-friendly agricultural sustainability and provides a promising alternative to conventional chemical fertilizers.