Liu Bin, Liu Xingwang, Yang Sen, Chen Chunhua, Xue Shudan, Cai Yanling, Wang Dandan, Yin Shuai, Gai Xinshuang, Ren Huazhong
Department of Vegetable Science, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China.
Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops of Beijing, China Agricultural University, Beijing, 100193, China.
New Phytol. 2016 Apr;210(2):551-63. doi: 10.1111/nph.13801. Epub 2015 Dec 24.
Gibberellins are phytohormones with many roles, including the regulation of fruit development. However, little is known about the relationship between GA perception and fleshy fruit ontogeny, and particularly locule formation. We characterized the expression of cucumber (Cucumis sativus) GA receptor gene (CsGID1a) using quantitative real-time PCR, in situ hybridization and a promoter::β-glucuronidase (GUS) assay. CsGID1a-RNAi cucumber fruits were observed by dissecting microscope, scanning electron microscopy and transmission electron microscopy. Finally, genome-wide gene expression in young fruits from a control and the RNAi line was compared using a digital gene expression (DGE) analysis approach. The expression pattern of CsGID1a was found to be closely correlated with fruit locule formation, and silencing CsGID1a in cucumber resulted in fruits with abnormal carpels and locules. Overexpression of CsGID1a in the Arabidopsis thaliana double mutant (gid1a gid1c) resulted in 'cucumber locule-like' fruits. The DGE analysis suggested that expression of genes related to auxin synthesis and transport, as well as the cell cycle, was altered in CsGID1a-RNAi fruits, a result that was supported by comparing the auxin content and cellular structures of the control and transgenic fruits. This study demonstrates a previously uncharacterized GA signaling pathway that is essential for cucumber fruit locule formation.
赤霉素是一类具有多种作用的植物激素，包括对果实发育的调控。然而，关于赤霉素感知与肉质果实个体发育之间的关系，尤其是子房室形成的关系，我们了解甚少。我们运用定量实时PCR、原位杂交以及启动子::β-葡萄糖醛酸酶（GUS）分析，对黄瓜（Cucumis sativus）赤霉素受体基因（CsGID1a）的表达进行了表征。通过解剖显微镜、扫描电子显微镜和透射电子显微镜观察了CsGID1a-RNAi黄瓜果实。最后，使用数字基因表达（DGE）分析方法比较了对照和RNAi系幼果的全基因组基因表达。结果发现，CsGID1a的表达模式与果实子房室形成密切相关，黄瓜中CsGID1a基因沉默导致果实心皮和子房室异常。在拟南芥双突变体（gid1a gid1c）中过表达CsGID1a会产生“黄瓜子房室样”果实。DGE分析表明，CsGID1a-RNAi果实中与生长素合成和运输以及细胞周期相关的基因表达发生了改变，通过比较对照果实和转基因果实的生长素含量及细胞结构，这一结果得到了证实。本研究揭示了一条此前未被表征的对黄瓜果实子房室形成至关重要的赤霉素信号通路。
