Halomonas Rhizobacteria of Avicennia marina of Indian Sundarbans Promote Rice Growth Under Saline and Heavy Metal Stresses Through Exopolysaccharide Production

Researchers discovered that Halomonas rhizobacteria from the Sundarbans' Avicennia marina mangroves significantly promote rice growth under combined saline and arsenic stress conditions. The key mechanism involves the bacteria's production of exopolysaccharides (EPS), which enhances osmotic tolerance and sequesters arsenic, thereby mitigating toxicity. The study demonstrated a positive feedback loop where salt and arsenic stresses trigger EPS production, which in turn improves plant resilience. Through in vivo and in vitro assays, purified EPS was shown to effectively bind salt and arsenic, with characterization via FT-IR and SEM-EDX confirming its substrate-binding properties. Pot experiments further validated that both the bacteria and pure EPS individually enhance rice growth, underscoring EPS's direct role in stress mitigation and plant promotion.

Mukherjee, P., Mitra, A., & Roy, M. (2019). Halomonas Rhizobacteria of Avicennia marina of Indian Sundarbans Promote Rice Growth Under Saline and Heavy Metal Stresses Through Exopolysaccharide Production. Frontiers in Microbiology, 10. https://doi.org/10.3389/fmicb.2019.01207