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, PR 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, PR China.
Plant Sci. 2021 Jan;302:110695. doi: 10.1016/j.plantsci.2020.110695. Epub 2020 Oct 17.
Freezing stress is a major environmental factor that threatens the growth and development of fruit trees. MdMYB88 and its paralogue MdMYB124 have been identified as pivotal regulators in apple (Malus × domestica) freezing stress tolerance. Here, we demonstrated that a target of MdMYB88 and MdMYB124, TIME FOR COFFEE (TIC), contributes to freezing tolerance in apple. MdMYB88 and MdMYB124 directly bound the MdTIC promoter and positively regulated its expression under cold conditions. MdTIC RNAi plants displayed reduced freezing tolerance when MdTIC expression was repressed. Moreover, MdTIC RNAi plants lowered antioxidant enzyme activity. Transcriptome profiling revealed altered expression of cold-responsive genes in MdTIC RNAi plants under cold conditions, including MdPLC2, MdMKK2, and MdICE1. We also discovered that disordered MdTIC expression changed the saturation of fatty acids. Taken together, our data suggest that MdTIC is required for apple to tolerate freezing by mediating the expression of cold-responsive genes and fatty acid composition.
冻胁迫是威胁果树生长发育的主要环境因素。MdMYB88 和其同源物 MdMYB124 已被鉴定为苹果（Malus × domestica）抗冻胁迫的关键调节因子。在这里，我们证明了 MdMYB88 和 MdMYB124 的一个靶标 TIME FOR COFFEE（TIC）有助于苹果的抗冻性。MdMYB88 和 MdMYB124 直接结合 MdTIC 启动子，并在低温条件下正向调节其表达。当 MdTIC 的表达受到抑制时，MdTIC RNAi 植株的抗冻性降低。此外，MdTIC RNAi 植株降低了抗氧化酶的活性。转录组分析显示，在低温条件下，MdTIC RNAi 植株中冷响应基因的表达发生改变，包括 MdPLC2、MdMKK2 和 MdICE1。我们还发现，MdTIC 表达的紊乱改变了脂肪酸的饱和度。综上所述，我们的数据表明，MdTIC 通过调节冷响应基因和脂肪酸组成来介导苹果对冻胁迫的耐受。
