Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China.
Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China.
Plant Sci. 2020 Dec;301:110634. doi: 10.1016/j.plantsci.2020.110634. Epub 2020 Sep 1.
E-class MADS-box transcription factors, SEPALLATA (SEP) genes have an important role in floral organ initiation and development and fruit ripening. In this study, four sweet cherry SEP-like genes (PaMADS2, PaMADS4, PaMADS5, and PaMADS7) were cloned and functionally characterized. Gene expression analysis showed that the differential expression levels of PaMADS4 and PaMADS7 coincided with fruit ripening, and expression of PaMADS2 and PaMADS5 did not. Expression of PaMADS7 was affected by ABA and IAA. Subcellular localization assay demonstrated that four sweet cherry SEP-like proteins were all localized inside the nucleus. Silencing PaMADS7 using TRV-mediated virus-induced gene silencing inhibited fruit ripening and influenced major ripening-related physiological processes, such as ABA content, soluble sugar contents, fruit firmness, and anthocyanin content, as well as expression of ripening-related genes. In addition, silencing of PaMADS7 induced phenotype defects that suppressed fruit ripening, which were rescued by exogenous ABA. Furthermore, yeast one-hybrid assay (Y1H) and transient expression analyses revealed that PaMADS7 directly binds to the promoter of PaPG1, which is involved in sweet cherry fruit softening, and positively activated PaPG1expression. These results showed that PaMADS7 is an indispensable positive regulator of sweet cherry fruit ripening and softening.
E 类 MADS 框转录因子 SEPALLATA（SEP）基因在花器官起始和发育以及果实成熟中具有重要作用。本研究克隆并功能表征了四个甜樱桃 SEP 样基因（PaMADS2、PaMADS4、PaMADS5 和 PaMADS7）。基因表达分析表明，PaMADS4 和 PaMADS7 的差异表达水平与果实成熟相吻合，而 PaMADS2 和 PaMADS5 的表达则没有。PaMADS7 的表达受 ABA 和 IAA 的影响。亚细胞定位实验表明，四个甜樱桃 SEP 样蛋白均定位于细胞核内。使用 TRV 介导的病毒诱导基因沉默沉默 PaMADS7 抑制了果实成熟，并影响了主要的成熟相关生理过程，如 ABA 含量、可溶性糖含量、果实硬度和花青素含量，以及成熟相关基因的表达。此外，沉默 PaMADS7 诱导了抑制果实成熟的表型缺陷，外源 ABA 可挽救这些缺陷。此外，酵母单杂交（Y1H）和瞬时表达分析表明，PaMADS7 直接结合到参与甜樱桃果实软化的 PaPG1 启动子上，并正向激活 PaPG1 的表达。这些结果表明，PaMADS7 是甜樱桃果实成熟和软化所必需的正调控因子。
