Phytoremediation of Arsenic (As) in rice plants, mediated by  strain IU31 through antioxidant responses and phytohormones synthesis

作者：Ihsan Ullah, Yasir Anwar, Muhammad Faisal Siddiqui, Nadiah Al-Sulami, Raza Ullah · 发表于：Environmental Pollution · 年份：2024 · DOI：10.1016/j.envpol.2024.124207 · 被引用次数：23 · 研究领域：Arsenic contamination and mitigation、Plant Stress Responses and Tolerance、Enzyme-mediated dye degradation

Bacteria-assisted phytoremediation uses bacteria to promote plant health and improve its ability to remediate toxic heavy metals like Arsenic (As). Here, we isolated rhizobacteria and identified them as Bacillus subtilis strain IU31 using 16S rDNA sequencing. IU31 showed phosphate solubilization potential on Pikovskaya agar medium and produced siderophores , which were detected on Chromium Azurol-S (CAS) agar medium. Indole-3-acetic acid (IAA) and gibberellins (GAs), namely GA 1 , GA 3 , GA 4 , GA 7 , GA 9 , GA 12 , GA 15 , and GA24, were quantified by GC/MS-SIM analysis. The expression levels of genes involved in GA and IAA biosynthesis , such as cyp112, cyp114 , trpA, and trpB , were assessed using semi-quantitative RT-PCR. Plant bioassays showed that As at a 15 mg/kg concentration reduced plant growth, chlorophyll content, and biomass. However, IU31 inoculation significantly improved plant growth dynamics, enhancing As accumulation by up to 50% compared with uninoculated plants. IU31 inoculation induced the bioconcentration factor (BCF) and bioaccumulation factor (BAF) of As in plants compared to uninoculated plants, but the translocation factor (TF) of As was unaffected by IU31 inoculation. IU31 inoculation effectively restored glutathione-S-transferase (GST) and catalase (CAT) enzyme activities , as well as glutathione (GSH) and hydrogen peroxide concentrations to nearly normal levels, which were significantly elevated in plants exposed to As stress. These results show t...