Department of Vegetable Sciences, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing 100193, China.
New Phytol. 2018 Apr;218(1):344-356. doi: 10.1111/nph.14954. Epub 2017 Dec 23.
Cucumber (Cucumis sativus) is an agronomically important vegetable with indeterminant growth habit, in which leaves are produced from the shoot apical meristem (SAM), and unisexual flowers are generated from the leaf axils. LEAFY (LFY) and its homologs have been shown to play important roles in promoting flower development and branching. The LFY homolog gene CsLFY was cloned in cucumber. Molecular biology, developmental biology and biochemical tools were combined to explore the biological function of the LFY homologous gene CsLFY in cucumber. CsLFY was expressed in the SAM, floral meristem and floral organ primordia. Ectopic expression of CsLFY rescued the phenotype of the lfy-5 mutant in Arabidopsis. Knockdown of CsLFY by RNA interference (RNAi) led to defective shoot development and premature discontinuance of leaf initiation in cucumber. Transcription of CsWUS and putative CsLFY target genes including CsAP3 and CUM1 were significantly reduced in the CsLFY-RNAi lines. Further biochemical analyses indicated that CsLFY physically interacts with CsWUS in cucumber. These data suggested that CsLFY has a novel function in regulating shoot meristem maintenance through interaction with CsWUS, and promotes flower development via activation of CsAP3 and CUM1 in cucumber.
黄瓜（Cucumis sativus）是一种重要的农业蔬菜，具有不定生长习性，其叶片由茎尖分生组织（SAM）产生，而雌雄花则由叶腋产生。LEAFY（LFY）及其同源物已被证明在促进花发育和分枝方面发挥重要作用。在黄瓜中克隆了 LFY 同源基因 CsLFY。本文综合应用分子生物学、发育生物学和生物化学工具，探讨了 LFY 同源基因 CsLFY 在黄瓜中的生物学功能。CsLFY 在 SAM、花分生组织和花器官原基中表达。CsLFY 在拟南芥 lfy-5 突变体中的异位表达挽救了其表型。通过 RNA 干扰（RNAi）敲低 CsLFY 导致黄瓜中芽发育缺陷和叶片起始过早停止。CsLFY-RNAi 系中 CsWUS 和推定的 CsLFY 靶基因包括 CsAP3 和 CUM1 的转录明显降低。进一步的生化分析表明，CsLFY 在黄瓜中与 CsWUS 发生物理相互作用。这些数据表明，CsLFY 通过与 CsWUS 的相互作用，在调控茎分生组织维持方面具有新的功能，并通过激活 CsAP3 和 CUM1 在黄瓜中促进花发育。
