Arsenite-Oxidizing Bacterium Boosts Rice Resilience by Reshaping the Ionomic and Transcriptomic Homeostasis to...

Area of Science:

• Environmental Microbiology
• Plant Science
• Biochemistry

Background:

• Arsenic (As) contamination in rice poses risks to human health and agriculture.
• Arsenite (AsIII)-oxidizing bacteria offer a promising strategy for arsenic mitigation in rice.
• The molecular mechanisms underlying bacterial arsenic mitigation in rice are not well understood.

Purpose of the Study:

• To investigate the effects of arsenite-oxidizing bacterium SMS11 on arsenic accumulation and rice plant physiology.
• To elucidate the molecular mechanisms, including ionomic and transcriptomic changes, involved in SMS11-mediated arsenic mitigation.
• To assess the potential of SMS11 for enhancing rice resilience to arsenic stress.

Main Methods:

• Soil pot and hydroponic experiments were conducted using rice plants and arsenite-oxidizing bacterium SMS11.
• Arsenic levels in soil, porewater, and rice tissues were quantified.
• Ionomic analysis (ion content) and transcriptomic analysis (gene expression) were performed on rice shoots and roots.

Main Results:

• SMS11 inoculation reduced porewater arsenic by 94.8% and shoot arsenic by 40.6%, while increasing shoot biomass by 78.3%.
• SMS11 mitigated AsIII-induced alterations in essential ion content (P, K, Mg, Ca) in rice.
• Transcriptomic analysis revealed significant downregulation of arsenic accumulation genes and restoration of disrupted biological processes, including oxidative stress response and photosynthesis.

Conclusions:

• Inoculation with arsenite-oxidizing bacterium SMS11 effectively mitigates arsenic accumulation in rice plants.
• SMS11 enhances rice resilience to arsenic stress by modulating ionomic and transcriptomic homeostasis.
• This study provides molecular insights into bacterial-mediated arsenic mitigation, paving the way for agricultural applications.