The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agriculture and Food Science, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China.
State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China.
Plant Sci. 2021 May;306:110850. doi: 10.1016/j.plantsci.2021.110850. Epub 2021 Feb 16.
Autophagy is a major degradation pathway in plants for maintaining cellular homeostasis in response to various environmental stressors. ATG8 is one of a series of autophagy-related (ATG) proteins and plays a central role in both bulk and selective autophagy. Previously, we characterized MdATG8i in apple and demonstrated that it has a positive role in apple stress resistance. Although many ATG8-interacting proteins have been found in Arabidopsis, no protein has been reported to interact with MdATG8 in apple. Here, we identified MdHARBI1 as a MdATG8i-interacting protein in apple, however, the functions of HARBI1-like proteins have not been explored in plants. Expression analysis of MdHARBI1 and pro-MdHARBI1-GUS staining of transgenic Arabidopsis exposed to high temperature demonstrated that MdHARBI1 was significantly induced by heat stress. Moreover, heat-treated MdHARBI1-trangenic tomato plants maintained higher autophagic activity, accumulated fewer ROS, and displayed stronger chlorophyll fluorescence than wild-type plants. Because these phenotypes were consistent with those displayed by MdATG8i-overexpressing apple plants under high temperature, we concluded that the MdATG8i-interacting protein MdHARBI1 plays a critical role in the basal thermotolerance of plants, mainly by influencing autophagy pathways.
自噬是植物中一种主要的降解途径，可用于维持细胞内环境平衡以响应各种环境胁迫。ATG8 是一系列自噬相关（ATG）蛋白之一，在 bulk 和选择性自噬中都发挥着核心作用。之前，我们在苹果中鉴定了 MdATG8i，并证实其在苹果的抗逆性中具有积极作用。尽管在拟南芥中已经发现了许多 ATG8 相互作用蛋白，但尚未有报道称在苹果中存在与 MdATG8 相互作用的蛋白。在这里，我们鉴定了 MdHARBI1 是苹果中的 MdATG8i 相互作用蛋白，然而，HARBI1 样蛋白的功能在植物中尚未被探索。对 MdHARBI1 的表达分析和转 MdHARBI1-GUS 基因拟南芥在高温下的染色显示，MdHARBI1 受到热胁迫的显著诱导。此外，与野生型植物相比，经热处理的 MdHARBI1 转基因番茄植物保持更高的自噬活性，积累更少的 ROS，显示出更强的叶绿素荧光。由于这些表型与高温下 MdATG8i 过表达苹果植物的表型一致，我们得出结论，MdATG8i 相互作用蛋白 MdHARBI1 通过影响自噬途径在植物的基础耐热性中起着关键作用。
