Zhang Xiaoqian, Ma Wanyun, Guan Xueqiang, Wang Fei, Fan Zongbao, Gao Shiwei, Yao Yuxin
State Key Laboratory of Crop Biology, Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China.
Shandong Academy of Grape/Shandong Technology Innovation Center of Wine Grape and Wine, Jinan, Shandong 250100, China.
Hortic Res. 2022 Dec 7;10(2):uhac274. doi: 10.1093/hr/uhac274. eCollection 2023 Feb.
This work demonstrated that melatonin increases continuously in seeds, particularly seed coats, during berry ripening. Exogenous melatonin treatments significantly increased the proanthocyanidin (PA) content, partially through ethylene signaling, in seed coats. expression exhibited patterns similar to melatonin accumulation over time, which was largely induced by melatonin treatment in seed coats during berry ripening. Additionally, VvMYB14 bound to the MBS element of the promoter to activate expression. overexpression largely upregulated expression of , and and increased the PA content in grape seed-derived calli. Similar increases in and expression and PA content were found in -overexpressing seeds. It was also observed that overexpression increased ethylene production and thereby induced expression of , which bound to the ERF element of the promoter and activated its expression. Additionally, suppression reduced the overexpression-induced increases in expression of and and PA content. Further experiments revealed that melatonin-induced increases in the expression of , , and and PA accumulation were significantly reduced in -suppressing grape calli and leaves. Collectively, VvMYB14 mediates melatonin-induced PA biosynthesis by directly transactivating expression and indirectly upregulating expression via VvERF104.
这项研究表明，在浆果成熟过程中，褪黑素在种子尤其是种皮中持续增加。外源褪黑素处理显著提高了种皮中原花青素（PA）的含量，部分是通过乙烯信号传导实现的。 的表达呈现出与褪黑素积累随时间变化相似的模式，在浆果成熟过程中，种皮中的褪黑素处理在很大程度上诱导了这种表达。此外，VvMYB14与 启动子的MBS元件结合以激活表达。 的过表达在很大程度上上调了 、 和 的表达，并增加了葡萄种子来源愈伤组织中的PA含量。在过表达 的种子中也发现了 和 表达以及PA含量的类似增加。还观察到 的过表达增加了乙烯的产生，从而诱导了 的表达， 与 启动子的ERF元件结合并激活其表达。此外， 的抑制降低了 过表达诱导的 和 表达以及PA含量的增加。进一步的实验表明，在抑制 的葡萄愈伤组织和叶片中，褪黑素诱导的 、 、 和 表达增加以及PA积累显著减少。总的来说，VvMYB14通过直接反式激活 的表达并通过VvERF104间接上调 的表达来介导褪黑素诱导的PA生物合成。
