APETALA2基因对油菜种子含油量及种子发育影响的研究

Oil content in Brassica napus is a quantitative trait cintrolled by many genes, therefore the screening of regulatory genes has become more and more important in recent year. AP2 is the founding member of a large family of transcription factors and AP2 activity in Arabidopsis has been shown to affect not only floral meristem and floral organ identity and development but also in seed mass and oil content. Up to date, researches on AP2 have been focused on Arabidopsis and little is known about AP2 in Brassica napus. To investigate the effects of B. napus AP2 on embryo and seed development and oil content, BnAP2 gene was isolated by PCR and was inserted into the RNAi vector with seed specific napin promoter, and then the RNAi construct was introduced into oilseed rape by Agrobacterium tumefaciens transformation method to down-regulate the seed AP2 expression. The research will be of great significance for rapeseed breeding on oil content.

油菜含油量属于微效多基因控制的数量性状，通过导入单个或少数几个基因很难使油菜含油量得到大幅度的提高，因而筛选含油量的调控因子成为国内外研究热点。AP2在拟南芥所有营养器官及种子发育的各个阶段都有表达，它不仅决定花器官的发育、花器官数量，而且影响种子的产量和含油量。而AP2对油菜种子的发育及含油量影响目前尚无报道，因此本研究将通过构建带有种子特异性napin启动子和组成型启动子35S的AP2-hpRNAi 载体并将发夹 (hairpin) 载体引入油菜，使其在油菜细胞中转录成发夹RNA（hpRNA），从而特异性抑制AP2基因在油菜种子中的表达，探讨AP2基因在油菜种皮及胚发育和油脂积累过程中的作用，为提高油菜种子含油量奠定基础。

中文摘要: 植物油不仅是人类饮食的主要组成部分，还在工业和生物能源上有很好的应用和发展前景。因此提高含油量育种始终是油菜育种工作者关注的重要问题。由于种子含油量是受多基因控制的，长期以来利用调控种子脂肪酸代谢中的关键酶基因来达到提高含油量的效果并不理想，但通过转录因子对相关代谢途径的基因进行遗传修饰，可以更有效地达到提高含油量的目的, 本课题针对这一研究状况，从甘蓝型油菜中克隆到了控制含油量的重要转录因子AP2基因，通过构建AP2基因的RNA干扰载体和超表达载体转化到甘蓝型油菜中，一方面验证AP2基因对油菜含油量的影响，另一方面获得高含油量的育种材料，主要结果如下：（1） AP2基因影响花器官的发育，油菜转基因植株表现出花的多种表型改变和育性的降低；（2 ）干扰AP2基因表达影响角果和种子的发育，转化后代材料中角果长度、种子大小和千粒重明显增加；（3 ）AP2基因影响油菜种子含油量的积累，干扰AP2基因油菜种子含油量升高，获得了一批含油量升高的转基因材料。