Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100093, People's Republic of China.
Plant Physiol. 2023 Jul 3;192(3):2203-2220. doi: 10.1093/plphys/kiad147.
Drought and cold stresses seriously affect tree growth and fruit yield during apple (Malus domestica) production, with combined stress causing injury such as shoot shriveling. However, the molecular mechanism underlying crosstalk between responses to drought and cold stress remains to be clarified. In this study, we characterized the zinc finger transcription factor ZINC FINGER OF ARABIDOPSIS THALIANA 10 (ZAT10) through comparative analysis of shoot-shriveling tolerance between tolerant and sensitive apple rootstocks. MhZAT10 responded to both drought and cold stresses. Heterologous expression of MhZAT10 in the sensitive rootstock 'G935' from domesticated apple (Malus domestica) promoted shoot-shriveling tolerance, while silencing of MhZAT10 expression in the tolerant rootstock 'SH6' of Malus honanensis reduced stress tolerance. We determined that the apple transcription factor DEHYDRATION RESPONSE ELEMENT-BINDING PROTEIN 2A (DREB2A) is a direct regulator activating the expression of MhZAT10 in response to drought stress. Apple plants overexpressing both MhDREB2A and MhZAT10 genes exhibited enhanced tolerance to drought and cold stress, while plants overexpressing MhDREB2A but with silenced expression of MhZAT10 showed reduced tolerance, suggesting a critical role of MhDREB2A-MhZAT10 in the crosstalk between drought and cold stress responses. We further identified drought-tolerant MhWRKY31 and cold-tolerant MhMYB88 and MhMYB124 as downstream regulatory target genes of MhZAT10. Our findings reveal a MhDREB2A-MhZAT10 module involved in crosstalk between drought and cold stress responses, which may have applications in apple rootstock breeding programs aimed at developing shoot-shriveling tolerance.
干旱和寒冷胁迫严重影响苹果（Malus domestica）生产中的树木生长和果实产量，复合胁迫会导致梢干枯等伤害。然而，干旱和冷胁迫响应之间串扰的分子机制仍有待阐明。在这项研究中，我们通过比较耐干旱和寒冷胁迫的苹果砧木之间的梢干枯耐受性，对锌指转录因子拟南芥 ZAT10 进行了特征描述。MhZAT10 对干旱和寒冷胁迫均有响应。在驯化苹果（Malus domestica）的敏感砧木‘G935’中异源表达 MhZAT10 促进了梢干枯耐受性，而在耐干旱胁迫的砧木‘SH6’中沉默 MhZAT10 表达则降低了胁迫耐受性。我们确定苹果转录因子脱水响应元件结合蛋白 2A（DREB2A）是直接激活 MhZAT10 表达以响应干旱胁迫的调节因子。同时过表达 MhDREB2A 和 MhZAT10 基因的苹果植株对干旱和寒冷胁迫表现出增强的耐受性，而过表达 MhDREB2A 但沉默 MhZAT10 表达的植株则表现出降低的耐受性，表明 MhDREB2A-MhZAT10 在干旱和寒冷胁迫响应之间的串扰中起着关键作用。我们进一步鉴定了耐旱的 MhWRKY31 和耐寒的 MhMYB88、MhMYB124 作为 MhZAT10 的下游调控靶基因。我们的研究结果揭示了一个涉及干旱和寒冷胁迫响应之间串扰的 MhDREB2A-MhZAT10 模块，该模块可能在旨在开发梢干枯耐受性的苹果砧木选育计划中具有应用前景。
