Arsenite (AsIII)-oxidizing bacteria show great potential for mitigating arsenic (As) accumulation in rice plants; however, their molecular mechanisms remain unclear. In this study, our soil pot experiment demonstrated that inoculation with the AsIII-oxidizing bacterium SMS11 decreased porewater As by 94.8% (from 448 to 23.4 μg·kg-1), further reducing shoot As by 40.6% (from 6.02 to 3.58 mg·kg-1) and increasing shoot biomass by 78.3% (from 2.34 to 4.17 g). In the hydroponic experiment, ionomics revealed that SMS11 inoculation mitigated AsIII-induced changes in the ion content (e.g., P, K, Mg, and Ca) in both rice shoots and roots. Transcriptomics showed an 85% decrease in differentially expressed genes (8332 vs 1247) in shoots. Additionally, key As accumulation genes (e.g., OsLsi1, OsPT4, OsPT8, and OsHAC4) were downregulated by 26.9-84.0%, and disrupted biological processes (e.g., oxidative stress response, ion binding, and photosynthesis) were restored. Altogether, SMS11 inoculation boosts rice resilience by reshaping ionomic and transcriptomic homeostasis under AsIII stress.
Lin et al. (2025) studied this question.