Provincial Key Laboratory of the Biodiversity Study and Ecology Conservation in Southwest Anhui Province, Anqing Normal University, Anqing, China.
College of Resources and Environment, Anqing Normal University, Anqing, China.
Ecotoxicol Environ Saf. 2024 Oct 15;285:117102. doi: 10.1016/j.ecoenv.2024.117102. Epub 2024 Sep 26.
Cadmium (Cd) is a hazardous heavy metal that threatens human health through the consumption of contaminated rice. To mitigate Cd accumulation in rice grains, it is crucial to reduce Cd uptake. Nevertheless, the transcriptional mechanisms governing Cd uptake in rice remain largely unknown. This research identifies the transcription factor OsNAC5 in Oryza sativa as a positive regulator of the Cd transporter gene OsNRAMP1, thereby influencing Cd uptake. OsNAC5 is predominantly expressed in the roots, resides in the nucleus, and is upregulated by Cd-induced hydrogen peroxide (HO). Knocking out OsNAC5 results in lower Cd concentrations in both shoots and roots and heightens sensitivity to Cd. The expression of OsNRAMP1, enhanced by Cd stress, is dependent on OsNAC5. OsNAC5 binds to "CATGTG" motifs in the OsNRAMP1 promoter, activating its expression. The loss of OsNAC5 function leads to reduced Cd accumulation in rice grains. Our findings provide insights into the transcriptional regulation of Cd stress response in rice and propose biotechnological strategies to lower Cd uptake in crops.
镉（Cd）是一种有害的重金属，通过食用受污染的大米会威胁到人类健康。为了减轻大米中镉的积累，减少镉的吸收至关重要。然而，水稻中镉吸收的转录机制在很大程度上仍不清楚。本研究在水稻中鉴定出转录因子 OsNAC5 是 Cd 转运蛋白基因 OsNRAMP1 的正调控因子，从而影响 Cd 的吸收。OsNAC5 在根中表达为主，位于核内，并被 Cd 诱导的过氧化氢（HO）上调。敲除 OsNAC5 会导致地上部和根部的 Cd 浓度降低，并增加对 Cd 的敏感性。在 Cd 胁迫下，OsNRAMP1 的表达增强依赖于 OsNAC5。OsNAC5 结合到 OsNRAMP1 启动子上的“CATGTG”基序，激活其表达。OsNAC5 功能丧失会导致水稻籽粒中 Cd 积累减少。我们的研究结果为水稻 Cd 胁迫反应的转录调控提供了新的见解，并提出了降低作物 Cd 吸收的生物技术策略。
