Yu Qinhan, Zheng Qiaoling, Liu Chang, Zhang Junxia, Xie Yaping, Yao Wenkong, Li Jiaxin, Zhang Ningbo, Hao Xinyi, Xu Weirong
School of Life Sciences, Ningxia University, Yinchuan, Ningxia 750021, China.
College of Enology and Horticulture, Ningxia University, Yinchuan, Ningxia 750021, China.
Plant Physiol. 2025 Feb 7;197(2). doi: 10.1093/plphys/kiaf035.
Cold stress severely impacts the quality and yield of grapevine (Vitis L.). In this study, we extend our previous work to elucidate the role and regulatory mechanisms of Vitis amurensis MYB transcription factor 4a (VaMYB4a) in grapevine's response to cold stress. Our results identified VaMYB4a as a key positive regulator of cold stress. We demonstrated that VaMYB4a undergoes phosphorylation by V. amurensis calcineurin B-like (CBL) proteins-interacting protein kinase 18 (VaCIPK18) under cold stress, a process that activates VaMYB4a transcriptional activity. Using chromatin immunoprecipitation sequencing (ChIP-seq). We performed a comprehensive genomic search to identify downstream components that interact with VaMYB4a, leading to the discovery of a basic helix-loop-helix transcription factor, V. amurensis phytochrome-interacting factor 3 (VaPIF3). VaMYB4a attenuated the transcriptional activity of VaPIF3 through a phosphorylation-dependent interaction under cold conditions. Furthermore, VaPIF3, which interacts with and inhibits V. amurensis C-repeat binding factor 4 (VaCBF4, a known positive regulator of cold stress), has its activity attenuated by VaMYB4a, which mediates the modulation of this pathway. Notably, VaMYB4a also interacted with and promoted the expression of VaCBF4 in a phosphorylation-dependent manner. Our study shows that VaMYB4a positively modulates cold tolerance in plants by simultaneously downregulating VaPIF3 and upregulating VaCBF4. These findings provide a nuanced understanding of the transcriptional response in grapevine under cold stress and contribute to the broader field of plant stress physiology.
低温胁迫严重影响葡萄（葡萄属）的品质和产量。在本研究中，我们扩展了之前的工作，以阐明山葡萄MYB转录因子4a（VaMYB4a）在葡萄对低温胁迫响应中的作用和调控机制。我们的结果确定VaMYB4a是低温胁迫的关键正向调节因子。我们证明，在低温胁迫下，VaMYB4a会被山葡萄类钙调神经磷酸酶B蛋白相互作用蛋白激酶18（VaCIPK18）磷酸化，这一过程激活了VaMYB4a的转录活性。利用染色质免疫沉淀测序（ChIP-seq），我们进行了全面的基因组搜索，以鉴定与VaMYB4a相互作用的下游成分，从而发现了一种基本的螺旋-环-螺旋转录因子，即山葡萄光敏色素相互作用因子3（VaPIF3）。在低温条件下，VaMYB4a通过磷酸化依赖性相互作用减弱了VaPIF3的转录活性。此外，与山葡萄C-重复结合因子4（VaCBF4，一种已知的低温胁迫正向调节因子）相互作用并抑制其活性的VaPIF3，其活性被VaMYB4a减弱，VaMYB4a介导了该途径的调控。值得注意的是，VaMYB4a还以磷酸化依赖性方式与VaCBF4相互作用并促进其表达。我们的研究表明，VaMYB4a通过同时下调VaPIF3和上调VaCBF4来正向调节植物的耐寒性。这些发现为低温胁迫下葡萄的转录反应提供了细致入微的理解，并为植物胁迫生理学这一更广泛的领域做出了贡献。
