Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400085, India; School of Biological sciencesUM-DAE Center for Excellence in Basic Sciences, University of Mumbai, Vidyanagari 400098, Mumbai.
Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400085, India; Division of crop production, ICAR- Indian Institute of Soybean Research, Khandwa Road, Indore 452001, (M.P), India.
J Hazard Mater. 2022 Aug 5;435:129020. doi: 10.1016/j.jhazmat.2022.129020. Epub 2022 Apr 27.
Arsenic (As) is a ubiquitous carcinogenic metalloid that enters into human food chain, through rice consumption. To unravel the conundrum of oxidative vs. reductive stress, the differential root-system architecture (RSA) was studied under As (a ROS producer) and thiourea (TU; a ROS scavenger) alone treatments, which indicated 0.80- and 0.74-fold reduction in the number of lateral roots (NLR), respectively compared with those of control. In case of As+TU treatment, NLR was increased by 4.35-fold compared with those of As-stress, which coincided with partial restoration of redox-status and auxin transport towards the root-tip. The expression levels of 16 ROS related genes, including RBOHC, UPB-1 C, SHR1, PUCHI, were quantified which provided the molecular fingerprint, in accordance with endogenous ROS signature. LC-MS based untargeted and targeted metabolomics data revealed that As-induced oxidative stress was metabolically more challenging than TU alone-induced reductive stress. Cis/trans-ferruloyl putrescine and γ-glutamyl leucine were identified as novel As-responsive metabolites whose levels were decreased and increased, respectively under As+TU than As-treated roots. In addition, the overall amino acid accumulation was increased in As+TU than As-treated roots, indicating the improved nutritional availability. Thus, the study revealed dynamic interplay between "ROS-metabolites-RSA", to the broader context of TU-mediated amelioration of As-stress in rice.
砷（As）是一种普遍存在的致癌类金属元素，通过食用大米进入人类食物链。为了解决氧化应激与还原应激之间的难题，我们分别单独用砷（一种 ROS 产生剂）和硫脲（TU；一种 ROS 清除剂）处理水稻根系，研究了根系形态结构（RSA）的差异。结果表明，与对照组相比，单独用砷和 TU 处理后，侧根（NLR）的数量分别减少了 0.80 倍和 0.74 倍。而砷和 TU 同时处理时，NLR 增加了 4.35 倍，与氧化还原状态和生长素向根尖运输的部分恢复相一致。定量分析了 16 个与 ROS 相关的基因（包括 RBOHC、UPB-1C、SHR1、PUCHI）的表达水平，为内源 ROS 特征提供了分子指纹图谱。基于 LC-MS 的非靶向和靶向代谢组学数据表明，砷引起的氧化应激比 TU 单独引起的还原应激在代谢上更具挑战性。顺/反式-阿魏酰腐胺和γ-谷氨酰亮氨酸被鉴定为新的砷反应代谢物，其水平在砷+TU 处理的根系中低于砷处理的根系。此外，砷+TU 处理的根系中总的氨基酸积累增加，表明营养物质的可用性得到改善。因此，该研究揭示了“ROS-代谢物-RSA”之间的动态相互作用，为 TU 介导的水稻缓解砷胁迫提供了更广泛的背景。
