Cucumber is dioecious by nature, having both male and female flowers, and is a model system for unisexual flower development. Knowledge related to male flowering is limited, but it is reported to be regulated by transcription factors and hormone signals. Here, we report functional characterization of the cucumber (Cucumis sativus) GL2-LIKE gene, which encodes a homeodomain leucine zipper (HD-ZIP) IV transcription factor that plays an important role in regulating male flower development. Spatial–temporal expression analyses revealed high-level expression of CsGL2-LIKE in the male flower buds and anthers. CsGL2-LIKE is closely related to AtGL2, which is known to play a key role in trichome development. However, ectopic expression of CsGL2-LIKE in Arabidopsis gl2-8 mutant was unable to rescue the gl2-8 phenotype. Interestingly, the silencing of CsGL2-LIKE delayed male flowering by inhibiting the expression of the florigen gene FT and reduced pollen vigor and seed viability. Protein–protein interaction assays showed that CsGL2-LIKE interacts with the jasmonate ZIM domain protein CsJAZ1 to form a HD-ZIP IV–CsJAZ1 complex. Collectively, our study indicates that CsGL2-LIKE regulates male flowering in cucumber, and reveals a novel function of a HD-ZIP IV transcription factor in regulating male flower development of cucumber.

中文翻译：

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HD-ZIP IV转录因子GL2-LIKE调节黄瓜的雄花期和繁殖力。

黄瓜天生雌雄异体，有雄花和雌花，是单性花发育的模型系统。与雄性开花有关的知识是有限的，但据报道受转录因子和激素信号调节。在这里，我们报告黄瓜（Cucumis sativus）GL2-LIKE基因的功能表征，该基因编码同源域亮氨酸拉链（HD-ZIP）IV转录因子，在调节雄性花的发育中起重要作用。时空表达分析表明，CsGL2-LIKE在雄性花蕾和花药中有高水平表达。CsGL2-LIKE与AtGL2紧密相关，AtGL2在trichome开发中起着关键作用。但是，异位表达的CsGL2-LIKE拟南芥中gl2-8突变体不能挽救gl2-8表型。有趣的是，CsGL2-LIKE的沉默通过抑制荧光原基因FT的表达并降低花粉活力和种子活力而延迟了雄性开花。蛋白质-蛋白质相互作用分析表明，CsGL2-LIKE与茉莉酸的ZIM域蛋白CsJAZ1相互作用，形成HD-ZIP IV-CsJAZ1复合物。总体而言，我们的研究表明CsGL2-LIKE调节黄瓜的雄花，并揭示HD-ZIP IV转录因子在调节黄瓜的雄花发育中的新功能。