Abstract：
The introduction of arsenic, a hazardous metalloid, into the soil system due to heavy industrialization has negatively affected agricultural productivity, resulting in limited crop yields. A recent breakthrough in stress-responsive hormones, specifically brassinosteroids, has extensively covered the role of antioxidant enzyme defense systems in heavy metal stress mitigation. Considering the antioxidant properties and metal complex formation abilities of polyphenols, our study focuses on examining their role in arsenate toxicity amelioration by 24-epibrassinolide. We demonstrate enhanced growth parameters of sodium arsenate-stressed seedlings upon application of 24-epibrassinolide, with increased root and shoot polyphenol levels analyzed by high-performance liquid chromatography. Specifically, the concentration of catechin, sinapic acid, 4-hydroxy benzoic acid, protocatechuic acid, 4-coumaric acid, and myricetin were elevated, indicating induction of phenylpropanoid signaling pathway. Further, we also report a decrease in the generation of superoxide anions and hydrogen peroxide validated the antioxidant effects of these metabolites through the nitrobluetetrazolium and diaminobenzidine staining method. In addition, evaluation of transcript level of genes encoding for specific enzymes of the phenylpropanoid pathway in shoot and root showed a significant upregulation in mRNA expression of phenylalanine ammonia-lyase-1, cinnamate-4-hydroxylase, and caffeic acid o-methyltransferase-1 upon exogenous application of 24-epibrassinolide in arsenate stressed Oryza sativa.
摘要：
砷的引入，一种危险的准金属，由于重工业化而进入土壤系统，对农业生产力产生了负面影响，导致作物产量有限。最近在应激反应荷尔蒙方面的突破，特别是油菜素类固醇，广泛涵盖了抗氧化酶防御系统在重金属胁迫缓解中的作用。考虑到多酚的抗氧化性能和金属络合物形成能力,我们的研究重点是研究它们在24-表油菜素内酯改善砷酸盐毒性中的作用。我们证明了施用24-表油菜素内酯后砷酸钠胁迫的幼苗的生长参数增强，通过高效液相色谱法分析了根和茎多酚含量的增加。具体来说,儿茶素的浓度，芥子酸,4-羟基苯甲酸,原儿茶酸，4-香豆酸,杨梅素升高了，提示苯丙素信号通路的诱导。Further,我们还报道了通过硝基蓝四唑和二氨基联苯胺染色方法，超氧阴离子和过氧化氢的产生减少，验证了这些代谢物的抗氧化作用。此外,在芽和根中编码苯丙素途径的特定酶的基因转录水平的评估显示，苯丙氨酸氨裂解酶-1，肉桂酸-4-羟化酶的mRNA表达显着上调，在砷酸盐胁迫的水稻中外源施用24-表油菜素内酯和咖啡酸o-甲基转移酶-1。
