College of Horticulture Science and Engineering, Shandong Agricultural University, Shandong, 271018, China.
College of Horticulture Science and Engineering, Shandong Agricultural University, Shandong, 271018, China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Huanghuai Region), Ministry of Agriculture and Rural Affairs, Shandong, 271018, China; Shandong Collaborative Innovation Center for Fruit and Vegetable Production with High Quality and Efficiency, Tai'an, Shandong, 271018, China.
Plant Physiol Biochem. 2024 Apr;209:108544. doi: 10.1016/j.plaphy.2024.108544. Epub 2024 Mar 19.
Flower abscission is an important developmental process that can significantly reduce the yield of horticultural plants. We previously reported that SmMYB113 is a key transcription factor promoting anthocyanin biosynthesis and improve fruit quality. However, the overexpression of SmMYB113 in eggplant increased flower drop rate and reduced fruit yield. Here, we elucidate the regulatory mechanisms of SmMYB113 on flower abscission in eggplant. RNA-seq analysis indicated that the regulation of flower abscission by SmMYB113 was associated with altered expression of genes related to ethylene biosynthesis and signal transduction, including ethylene biosynthetic genes SmACS1, SmACS8 and SmACO4. Then, the ethylene content in flowers and the function of ethephon (ETH, which promotes fruit ripening) and 1-Methylcyclopropene (1-MCP, which acts as an ethylene perception inhibitor) were analyzed, which revealed that SmMYB113 directly regulates ethylene-dependent flower abscission. Yeast one-hybrid and dual-luciferase assays revealed that SmMYB113 could directly bind to the promoters of SmACS1, SmACS8, and SmACO4 to activate their expression. Through construction of a yeast two-hybrid (Y2H) screening library, the protein SmERF38 was found to interact with SmMYB113, and verified by Y2H, bimolecular fluorescence complementation (BiFC), and luciferase complementation assay. Furthermore, dual-luciferase assays showed that SmERF38 enhanced the role of SmMYB113 on the promoters of SmACS1. Our results provided new insight into the molecular mechanism of flower abscission in eggplant.
花脱落是一个重要的发育过程，它会显著降低园艺植物的产量。我们之前报道过，SmMYB113 是一个促进花色苷生物合成和改善果实品质的关键转录因子。然而，在茄子中过表达 SmMYB113 会增加花脱落率并降低果实产量。在这里，我们阐明了 SmMYB113 对茄子花脱落的调控机制。RNA-seq 分析表明，SmMYB113 对花脱落的调控与乙烯生物合成和信号转导相关基因表达的改变有关，包括乙烯生物合成基因 SmACS1、SmACS8 和 SmACO4。然后，分析了花朵中的乙烯含量以及乙烯促进果实成熟的作用物乙稀磷（ETH）和作为乙烯感受抑制剂的 1-甲基环丙烯（1-MCP）的功能，结果表明 SmMYB113 直接调控依赖乙烯的花脱落。酵母单杂交和双荧光素酶报告基因 assays 显示 SmMYB113 可以直接结合 SmACS1、SmACS8 和 SmACO4 的启动子，激活它们的表达。通过构建酵母双杂交（Y2H）筛选文库，发现蛋白 SmERF38 与 SmMYB113 相互作用，并通过 Y2H、双分子荧光互补（BiFC）和荧光素酶互补测定进行验证。此外，双荧光素酶 assays 表明 SmERF38 增强了 SmMYB113 对 SmACS1 启动子的作用。我们的结果为茄子花脱落的分子机制提供了新的见解。
