Delineating Kocuria turfanensis 2M4 as a credible PGPR: a novel IAA-producing bacteria isolated from saline desert

摘要

Indole-3-acetic acid (IAA)-producing bacteria Kocuria turfanensis strain 2M4 was isolated from the rhizospheric soil of halotolerant plant Suaeda fruticosa from a unique saline desert of Little Rann of Kutch, Gujarat, India. Rhizobacteria was bright orange pigmented, gram-positive, coccoid, non-endospore forming, and aerobic in nature. 16S rRNA gene sequence analysis showed that 2M4 isolate matched best with type strain of K. turfanensis HO-9042T . Isolate optimally produced 38 µg ml−1 IAA when growth medium was supplemented with 600 µg ml−1 of L-tryptophan. Thin layer chromatography and Fourier transform infrared spectroscopy analysis were performed to corroborate IAA production. To characterize rhizobacterial isolate as a plant growth-promoting bacteria, it was tested for phosphate solubilization where it solubilized maximum 12 µg ml−1 phosphate in presence of fructose, produced 53 siderophore units under iron-free minimal MM9 medium and produced 1.8 µmol ml−1 ammonia in peptone water broth. Plant growth promotion by test isolate was studied on groundnut (Arachis hypogaea L.) under non-saline and saline soil. There was increase by 18 in total plant length and 30 in fresh biomass observed under non-saline control soil. Under saline soil, test isolate showed 17 increase in total length of the plant and 13 increase in fresh biomass.