Characterization of Endophytic Bacterium Serratia sp. HSTU BF3R4 and Unraveling its Growth-Promoting Potential on Eggplants (Solanum melongena) in Field Conditions

Abstract

Endophytic bacteria play a significant role in growth promoting, sustainable agriculture and environmental conservation. Harnessing their growth-promoting potential can reduce reliance on synthetic fertilizers, enhance crop productivity, and foster eco-friendly agricultural practices. In this study, we investigated the plant growth-promoting effects of the endophytic bacterium Serratia sp. strain HSTU-BF3R4 on brinjal (eggplant) plants through field applications, aiming to promotion of plant growth and increase their production. The isolated strain displayed numerous beneficial traits, including acetone production, catalase activity, and the ability to ferment sugars and urea. The HSTU-BF3R4 strain demonstrated positive correlations between indole-3-acetic acid (IAA) production and plant growth promotion, as well as nitrogen fixation and phosphate solubilization. Applying the Serratia sp. strain HSTU-BF3R4 solution significantly increased the growth rate of eggplants, leading to improved shoot and branch lengths, increased flower, fruit numbers and fruit weight. Whole-genome analysis revealed genetic features associated with plant growth promotion, stress tolerance, and nutrient acquisition, which supporting its potential as a valuable agricultural asset. Phylogenetic analysis demonstrated a close genetic relationship between Serratia sp. strain HSTU-BF3R4 and related species, while genomic comparisons revealed unique characteristics distinguishing it from closely related strains. The presence of essential plant growth-promoting and stress-tolerating genes in its genome sequence and emphasized its potential applications in agriculture and environmental sustainability. Overall, our findings shed lights on the diverse and beneficial role of endophytes, particularly Serratia sp. strain HSTU-BF3R4, in enhancing its crop productivity and promoting eco-friendly agricultural practices.