Decoding the functional diversity of plant growth-promoting bacterial communities in the soils of Western Ghats, Tamil Nadu, India
TL;DR
The findings unlock the core microbiome of soils of Western Ghats, which can be utilized to develop a synthetic microbial consortium to boost agricultural productivity.
Abstract
Western ghats in India, one of the world’s biodiversity hot spots is the reservoirs of microbial resources having agricultural and industrial significance. However, the diversity of plant growth-promoting microbial communities associated with the plants and soil in the Western Ghats is untapped vault. The current emphasis on natural farming is more depending on the indigenous microbial communities and their metabolic functions towards sustainable one -health. With this background, the present study examines the bacterial diversity of soils from the Western Ghats of Nilgiris, Coimbatore and Dindigul regions. Among the 10 soil samples collected (S1 to S10), three soil samples (S2, S4 and S6) representing respective three regions were subjected for metagenomic studies based on their distinct soil chemical and biological properties. The computational analysis of the metagenome revealed the core genus Bradhyrhizobium in all soil samples, while Trebonia, Arthrobacter, Streptomyces, and Pseudomonas are the next most abundant genera, which varied substantially. The results collectively demonstrate that soil sample from Dindigul harbours the richest and most diverse microbial community among the three regions. In culturable studies, a total of 101 bacterial isolates were obtained from 10 soil samples (S1 to S10). Among them four Gram-negative bacterial isolates showed potential plant growth-promoting attributes, such as Ammonia, Indole Acetic Acid, Hydrogen cyanide and siderophore production, phosphorus, potassium, and zinc solubilization. The 16S rDNA analysis revealed that the bacterial isolates were Pseudomonas glycinae S6B1, Pseudomonas tolaasii S2B3, Pseudomonas azotoformans S9H10, and Pseudomonas poae S10B2. The isolate, S10B2, exhibited the maximum inhibition, with 81.25%, 70.1%, and 35% against plant pathogenic fungi, Rhizoctonia solani, Sclerotium rolfsii, and Fusarium oxysporum, respectively, indicating strong biocontrol potential. The effect of bacterial inoculants on chick pea (Cicer arietinum var. JG 62), showed that P. glycinae S6B1 significantly promoted plant growth such as root length, shoot length, and fresh/dry biomass. These findings unlock the core microbiome of soils of Western Ghats, which can be utilized to develop a synthetic microbial consortium to boost agricultural productivity.