Tan Yiting, Wang Wenjuan, Tian Wenbo, Wang Beibei, Zhao Qifeng, Liang Jinjun, Zhao Wei, Wen Pengfei
College of Horticulture, Shanxi Agricultural University, Taigu 030801, China.
Shanxi Key Laboratory of Germplasm Improvement and Utilization in Pomology, Pomology Institute, Shanxi Agricultural University, Taiyuan 030031, China.
Plants (Basel). 2025 May 8;14(10):1409. doi: 10.3390/plants14101409.
Drought ranks among the key abiotic stresses that limit the growth and yield of grapevines ( L.). Flavonols, a class of antioxidants commonly found in grapevines, play a crucial role in combating drought stress. In this study, we characterized the function and regulatory mechanism of the grapevine in mediating flavonol biosynthesis in response to drought stress. encodes a protein of 468 amino acids with conserved bHLH-MYC_N and bHLH domains. Phylogenetic analysis confirmed its homology with the grapevine VviMYC2 and similarity in function. The expression of in 'Cabernet Sauvignon' grapevine seedling leaves increased initially and then decreased during prolonged drought stress. The homologous and heterologous transformation of in grape suspension cells, plants, tobacco leaves, and grapevine leaves demonstrated its ability to positively regulate flavonol biosynthesis and accumulation by promoting the expression of flavonol-related genes, thereby enhancing the drought tolerance of transgenic plants. Furthermore, VviMYC4 could bind to specific E-box sites on the promoters of and to improve their activities. This study highlights as a pivotal positive regulator of drought tolerance in grapevines and proposes that enhances the antioxidant and reactive oxygen species (ROS) scavenging abilities of grapevines in challenging environments and improves their stress resilience by mediating flavonol biosynthesis. Our findings offer crucial candidate genes and valuable insights for the molecular breeding of grapevine drought resistance.
干旱是限制葡萄生长和产量的关键非生物胁迫之一。黄酮醇是葡萄中常见的一类抗氧化剂，在应对干旱胁迫中起着至关重要的作用。在本研究中，我们对葡萄VviMYC4在介导黄酮醇生物合成以响应干旱胁迫中的功能和调控机制进行了表征。VviMYC4编码一个含有保守的bHLH-MYC_N和bHLH结构域的468个氨基酸的蛋白质。系统发育分析证实了它与葡萄VviMYC2的同源性和功能相似性。在“赤霞珠”葡萄幼苗叶片中，VviMYC4的表达在长期干旱胁迫期间先升高后降低。在葡萄悬浮细胞、拟南芥植株、烟草叶片和葡萄叶片中对VviMYC4进行同源和异源转化，证明它能够通过促进黄酮醇相关基因的表达来正向调节黄酮醇的生物合成和积累，从而增强转基因植物的耐旱性。此外，VviMYC4可以与FLS和DFR启动子上的特定E-box位点结合以提高它们的活性。本研究突出了VviMYC4作为葡萄耐旱性关键正向调节因子的作用，并提出VviMYC4通过介导黄酮醇生物合成增强了葡萄在挑战性环境中的抗氧化和活性氧（ROS）清除能力，并提高了它们的胁迫恢复力。我们的研究结果为葡萄抗旱分子育种提供了关键候选基因和有价值的见解。
