花药类胡萝卜素合成途径调控机理

花药是被子植物雄蕊产生花粉的特殊器官，为吸引昆虫和方便传粉，花粉表面通常覆盖有脂类、色素、挥发性物质等次生代谢物。近年来对花粉外壁孢粉素、类黄酮的生成机制研究较多，但对类胡萝卜素的形成仍知之甚少，主要原因是缺乏类胡萝卜素代谢突变体。我们新发现一个橙红色花药的荷花隐性突变体，是目前两千余个荷花品种中唯一具有橙红色花药的品种。检测发现，橙红色源于类胡萝卜素的积累，且类胡萝卜素仅在花药绒毡层和花粉表面积累。转录组检测发现类胡萝卜素合成代谢途径中的多个关键酶基因的表达上调，推测可能更上游的调控因子发生了突变。在此基础上，我们拟通过建立遗传群体进行定位，鉴定获得调控类胡萝卜素形成的因子，并阐明橙红色花药形成机制及遗传规律。研究结果将揭示类胡萝卜素参与花药和花粉发育的代谢和遗传调控方式，丰富对植物花药色泽组成及形成机制的认识，也为植物的杂交育种提供新的理论依据。

Anther is the important male reproductive organ of stamen to produce pollens in angiosperms. To attract insects and facilitate pollination, the outermost stratum of the pollen surface is mainly composed of lipids, pigments, aromatic substances, and other unknown compounds. In recent years, the mechanisms of sporopollen formation and flavonoids synthesis on pollen are deeply explored, however the mechanism on the formation of carotenoids is still poorly understood. The main reason is due to the lack of mutant of carotenoids. Recently, a recessive mutant with orange anther was explored in lotus, which was the unique cultivar with orange anther among more than 2000 cultivars of lotus so far. The orange color was caused by the increase of carotenoids content through the GC-MS analysis, and color only existed on the tapetal cells and pollen surface. Comparison with the transcriptome of yellowish anther, a number of key enzyme genes involved in carotenoids biosynthesis pathway were up-regulated, which implied that one or more upstream transcription factors may regulate the carotenoids metabolism. On this basis, we intend to establish a genetic population to find the transcriptional factors regulating the formation of carotenoids, and to clarify the formation mechanism of orange anther. This study will reveal the model for carotenoids metabolism and genetic regulation in anther and pollen development, enrich the understanding of the mechanism of plant anther color and composition, and provide theoretical guidance for plant cross breeding.