Regulation of fruit ripening by the brassinosteroid biosynthetic gene SlCYP90B3 via an ethylene-dependent pathway in tomato.
Regulation of fruit ripening by the brassinosteroid biosynthetic gene SlCYP90B3 via an ethylene-dependent pathway in tomato.
复制标题
DOI：
10.1038/s41438-020-00383-0
复制
发表时间：
2020
影响因子：
8.7
通讯作者：
Wang Q
中科院分区：
文献类型：
--
作者：
Hu S;Liu L;Li S;Shao Z;Meng F;Liu H;Duan W;Liang D;Zhu C;Xu T;Wang Q
乙烯在果实成熟过程中的重要作用已被深入研究。然而，油菜素甾醇（BR）在果实成熟的调控及其与乙烯途径的关系的参与知之甚少。在目前的研究中，我们发现BR在番茄果实成熟过程中活跃合成。然后，我们产生了过表达或沉默SlCYP 90 B3的转基因株系，SlCYP 90 B3编码细胞色素P450单加氧酶，催化BR合成的限速步骤。SlCYP 90 B3基因的表达水平与番茄果实中生物活性BR的含量以及果实的后熟过程（软化增强、可溶性糖和风味挥发物含量增加）呈正相关。类胡萝卜素积累和乙烯产生与SlCYP 90 B3的表达水平密切相关，这一点通过类胡萝卜素生物合成基因和乙烯途径基因在转基因番茄果实中的表达改变得到证实。然而，乙烯感知抑制剂1-甲基环丙烯（1-MCP）的应用取消了SlCYP 90 B3过表达对类胡萝卜素积累的促进作用。综上所述，这些结果增加了我们对SlCYP 90 B3参与番茄中生物活性BR生物合成以及果实成熟的理解，从而使SlCYP 90 B3成为用于改善番茄果实的视觉、营养和风味品质而没有产量损失的靶基因。
The essential role of ethylene in fruit ripening has been thoroughly studied. However, the involvement of brassinosteroids (BRs) in the regulation of fruit ripening and their relationship with the ethylene pathway are poorly understood. In the current study, we found that BRs were actively synthesized during tomato fruit ripening. We then generated transgenic lines overexpressing or silencing SlCYP90B3, which encodes a cytochrome P450 monooxygenase that catalyzes the rate-limiting step of BR synthesis. The expression level of SlCYP90B3 was positively related to the contents of bioactive BRs as well as the ripening process in tomato fruit, including enhanced softening and increased soluble sugar and flavor volatile contents. Both carotenoid accumulation and ethylene production were strongly correlated with the expression level of SlCYP90B3, corroborated by the altered expression of carotenoid biosynthetic genes as well as ethylene pathway genes in transgenic tomato fruits. However, the application of the ethylene perception inhibitor 1-methycyclopropene (1-MCP) abolished the promotion effect of SlCYP90B3 overexpression on carotenoid accumulation. Taken together, these results increase our understanding of the involvement of SlCYP90B3 in bioactive BR biosynthesis as well as fruit ripening in tomato, thus making SlCYP90B3 a target gene for improvement of visual, nutritional and flavor qualities of tomato fruits with no yield penalty.