黄瓜CsLOX1基因调控花器官发育的分子机制研究

Cucumber is an important vegetable crop, the research on cucumber floral organ will lay the foundation for elucidating the mechanism of reproductive development. Lipoxygenase (LOX) plays an important role in stress response and the formation of flavor substances, little is known about its function in floral organ development. Our previous studies revealed that, among 23 CsLOX members, only CsLOX1 showed a significant expression difference between the stage 6 male and female stamen primordia. The CsLOX1 overexpressing transgenic Arabidopsis exhibited new phenotypes with increasing pistil number, ectopically developed ovule and stigma in addition to the abnormal stamen development, indicated CsLOX1 had functional differentiation during cucumber floral organ development. Base on these findings, the study on in situ hybrid analysis, the morphological observation of CsLOX1 overexpression and RNAi interference transgenic cucumber flower, the measurement of hormone content, and the expression analysis of key genes involved in Jasmine acid, Ethylene, and Gibberellin pathways, will be carried out to further ascertain its function and molecular mechanism. Through this research, we expected to reveal the relationship of CsLOX1 with cucumber floral organ development in the theory, to provide theoretical support for cucumber genetic improvement in the application.

黄瓜是重要的蔬菜作物，对黄瓜花器官的研究将为阐明其生殖发育机制奠定基础。脂氧合酶基因（lipoxygenase, LOX）在逆境响应和风味物质的形成方面起重要作用，其在花器官发育中的功能还知之甚少。前期研究表明，在黄瓜23个CsLOX基因中，仅CsLOX1在花发育第6期的雄花和雌花雄蕊原基中具有显著的表达差异。过量表达CsLOX1的拟南芥除雄蕊发育异常外，还出现雌蕊数目增加、胚珠和柱头异位生长的新表型，暗示其在黄瓜花器官发育过程中出现了功能分化。本研究拟在已有的工作基础上，通过原位杂交、过表达和RNAi转基因黄瓜花器官的形态学观察、茉莉酸、乙烯和赤霉素含量的测定及各自信号途径关键基因的表达分析，进一步研究该基因的功能及分子机制。通过本研究，可望在理论上揭示该基因与黄瓜花器官发育之间的关系，在应用上为黄瓜的遗传改良提供理论支持。

黄瓜是重要的蔬菜作物，对黄瓜花器官的研究将为阐明其生殖发育机制奠定基础。脂氧合酶基因（lipoxygenase, LOX）在逆境响应和风味物质的形成方面起重要作用，其在花器官发育中的功能还知之甚少。研究表明，在黄瓜23个CsLOX基因中，仅CsLOX1在花发育第6期的雄花和雌花雄蕊原基中具有显著的表达差异。过量表达CsLOX1的拟南芥除雄蕊发育异常外，还出现雌蕊数目增加、胚珠和柱头异位生长的新表型。原位杂交显示，阳性信号较弱，雄蕊、雌蕊、胚珠等雄花花器官中的表达无显著性差异。过量表达CsLOX1黄瓜植株出现晚花现象，但是体视镜观察，开花后期与野生型比较，无明显差异。qRT-PCR检测发现，过量表达CsLOX1黄瓜花蕾中，选择检测的茉莉酸、乙烯等激素通路基因几乎全部上调，其中茉莉酸通路基因LOX1和AOS，乙烯通路基因ACS1，ACS2，CTR1 的表达上调情况最为显著。这些结果表明，CsLOX1基因可能在黄瓜花器官发育过程中出现了功能分化。