Research Center for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China.
Warwick-Hangzhou RNA Signaling Joint Laboratory, School of Life Sciences, University of Warwick, Warwick, CV4 7AL, United Kingdom.
J Integr Plant Biol. 2023 Oct;65(10):2262-2278. doi: 10.1111/jipb.13557. Epub 2023 Sep 13.
Cadmium (Cd) toxicity severely limits plant growth and development. Moreover, Cd accumulation in vegetables, fruits, and food crops poses health risks to animals and humans. Although the root cell wall has been implicated in Cd stress in plants, whether Cd binding by cell wall polysaccharides contributes to tolerance remains controversial, and the mechanism underlying transcriptional regulation of cell wall polysaccharide biosynthesis in response to Cd stress is unknown. Here, we functionally characterized an Arabidopsis thaliana NAC-type transcription factor, NAC102, revealing its role in Cd stress responses. Cd stress rapidly induced accumulation of NAC102.1, the major transcript encoding functional NAC102, especially in the root apex. Compared to wild type (WT) plants, a nac102 mutant exhibited enhanced Cd sensitivity, whereas NAC102.1-overexpressing plants displayed the opposite phenotype. Furthermore, NAC102 localizes to the nucleus, binds directly to the promoter of WALL-ASSOCIATED KINASE-LIKE PROTEIN11 (WAKL11), and induces transcription, thereby facilitating pectin degradation and decreasing Cd binding by pectin. Moreover, WAKL11 overexpression restored Cd tolerance in nac102 mutants to the WT levels, which was correlated with a lower pectin content and lower levels of pectin-bound Cd. Taken together, our work shows that the NAC102-WAKL11 module regulates cell wall pectin metabolism and Cd binding, thus conferring Cd tolerance in Arabidopsis.
镉（Cd）毒性严重限制了植物的生长和发育。此外，蔬菜、水果和粮食作物中 Cd 的积累对动物和人类的健康构成了威胁。尽管细胞壁已被认为与植物中的 Cd 胁迫有关，但细胞壁多糖与 Cd 结合是否有助于耐受仍存在争议，而且细胞壁多糖生物合成对 Cd 胁迫的转录调控机制尚不清楚。在这里，我们对拟南芥 NAC 型转录因子 NAC102 进行了功能表征，揭示了其在 Cd 胁迫反应中的作用。Cd 胁迫迅速诱导 NAC102.1 的积累，这是编码功能性 NAC102 的主要转录本，尤其是在根尖。与野生型（WT）植物相比，nac102 突变体表现出增强的 Cd 敏感性，而 NAC102.1 过表达植物则表现出相反的表型。此外，NAC102 定位于细胞核，直接与细胞壁相关激酶样蛋白 11（WAKL11）的启动子结合，并诱导转录，从而促进果胶的降解并减少果胶与 Cd 的结合。此外，WAKL11 的过表达恢复了 nac102 突变体的 Cd 耐受性，使其达到 WT 水平，这与较低的果胶含量和较低的果胶结合 Cd 水平相关。总之，我们的工作表明，NAC102-WAKL11 模块调节细胞壁果胶代谢和 Cd 结合，从而赋予拟南芥 Cd 耐受性。
