Chen Xiuxiu, Jin Songsong, Du Hong, Liu Zebin, Hou Congcong, Tang Ling, Wang Yuanyuan, Wang Yuxi, Yang Zhaolin, Zhao Tong, Ma Jinying, Zhang Lanjun, Li Meijing, Qi Dongdong, Li Wenlong, Wang Xiaohua, Sun Runze, Moore John P, Liu Yongxiu, Lin Jinxing, Deng Xin
State Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
Nat Plants. 2025 Aug 1. doi: 10.1038/s41477-025-02057-y.
Autophagy and apoplastic ascorbic acid (AsA) play important roles in plant drought tolerance. However, the trans-plasma membrane transport of AsA and its association with autophagy during drought stress are unclear. Here we report an AsA-induced autophagy pathway in plants, wherein plasma-membrane-located cytochrome b561 and DOMON domain (CYBDOM) proteins play positive roles. CYBDOM proteins from the resurrection plant Boea hygrometrica (BhDB) and Arabidopsis (AtDB1) can transport electrons across the plasma membrane using intracellular AsA as an electron donor and apoplastic monodehydroascorbic acid or Fe as electron acceptors in Xenopus laevis oocytes. Increased apoplastic AsA, autophagy and drought tolerance are observed in BhDB- and AtDB1-overexpressing Arabidopsis compared with the wild type. CYBDOM proteins interact with respiratory burst oxidase homologue D (RbohD), which serves as the adaptor to bind autophagy related gene 8 protein (ATG8) and cargo protein for autophagic degradation. AsA increases AtDB1 protein level and its interaction with RbohD. Together, the AsA-activated CYBDOM-RbohD synergy to induce autophagy suggests a novel mechanism in plant drought and desiccation tolerance.
自噬和质外体抗坏血酸（AsA）在植物耐旱性中发挥重要作用。然而，干旱胁迫期间AsA的跨质膜转运及其与自噬的关联尚不清楚。在此，我们报道了植物中一种AsA诱导的自噬途径，其中位于质膜的细胞色素b561和DOMON结构域（CYBDOM）蛋白发挥着积极作用。复苏植物牛耳草（BhDB）和拟南芥（AtDB1）的CYBDOM蛋白可以在非洲爪蟾卵母细胞中利用细胞内AsA作为电子供体，质外体单脱氢抗坏血酸或铁作为电子受体跨质膜转运电子。与野生型相比，在过表达BhDB和AtDB1的拟南芥中观察到质外体AsA增加、自噬和耐旱性增强。CYBDOM蛋白与呼吸爆发氧化酶同源物D（RbohD）相互作用，RbohD作为衔接子结合自噬相关基因8蛋白（ATG8）和货物蛋白进行自噬降解。AsA增加AtDB1蛋白水平及其与RbohD的相互作用。总之，AsA激活的CYBDOM-RbohD协同作用诱导自噬，提示了植物耐旱和耐干燥的一种新机制。
