MdHB7 ‐like positively modulates apple salt tolerance by promoting autophagic activity and Na + efflux

作者：Jie Yang, Lina Qiu, Quanlin Mei, Yunxia Sun, Na Li, Xiaoqing Gong, Fengwang Ma, Ke Mao · 发表于：The Plant Journal · 年份：2023 · DOI：10.1111/tpj.16395 · 被引用次数：33 · 研究领域：Plant Stress Responses and Tolerance、Plant responses to water stress、Postharvest Quality and Shelf Life Management

SUMMARY Salt stress adversely affects the yield and quality of crops and limits their geographical distribution. Studying the functions and regulatory mechanisms of key genes in the salt stress response is important for breeding crops with enhanced stress resistance. Autophagy plays an important role in modulating the tolerance of plants to various types of abiotic stressors. However, the mechanisms underlying salt‐induced autophagy are largely unknown. Cation/Ca 2+ exchanger proteins enhance apple salt tolerance by inhibiting Na + accumulation but the mechanism underlying the response to salt stress remains unclear. Here, we show that the autophagy‐related gene MdATG18a modulated apple salt tolerance. Under salt stress, the autophagic activity, proline content, and antioxidant enzyme activities were higher and Na + accumulation was lower in MdATG18a ‐overexpressing transgenic plants than in control plants. The use of an autophagy inhibitor during the salt treatment demonstrated that the regulatory function of MdATG18a depended on autophagy. The yeast‐one‐hybrid assay revealed that the homeodomain‐leucine zipper (HD‐Zip) transcription factor MdHB7‐like directly bound to the MdATG18a promoter. Transcriptional regulation and genetic analyses showed that MdHB7‐like enhanced salt‐induced autophagic activity by promoting MdATG18a expression. The analysis of Na + efflux rate in transgenic yeast indicated that MdCCX1 expression significantly promoted Na + efflux. Promoter binding, t...