Seed vigor-promoting Enterobacter sp. isolated from the eastern sub-Himalayan terai region serves a dual purpose of potassium solubilization and its retention

Abstract

Potassium (K)- solubilizing microbes release K from interlocked silicate clay minerals. These microbes also render it prone to leaching loss as K⁺ is highly water-soluble, especially in the sub-Himalayan Terai region, where rainfall is high. In this regard, K chelation by microbial exopolysaccharide can be an eco-friendly solution. It is known that members of Enterobacterales, which are relatively dominant during the rainy season, can be utilised to devise strategies to prevent K leaching. In this study, two species of soil-dwelling Enterobacter were isolated. Both isolates exhibited K solubilization and exopolysaccharide secretion. Using Salkowski chemistry, their IAA production was estimated (approx. 26 ppm). Furthermore, inoculated soils demonstrated nearly tenfold higher K retention compared to uninoculated controls, highlighting a role of EPS in nutrient binding. These findings reveal that soil-associated Enterobacterales contribute to nutrient availability, soil stability, and plant vigour under the unique conditions of the eastern sub-Himalayan Terai ecosystem.