2个小麦旗叶高表达的全新miRNA tae-miR5048和tae-miR9663的功能研究

miRNAs are essential regulators which regulate gene expression and are involved in plant growth and development. Flag leaves play important roles in the development of wheat reproductive organs and wheat yield. We have identified some novel miRNAs which highly express in flag leaves in wheat cv. Xiaoyan6, but how they regulate the growth and development of flag leaves and how they have impacts on wheat quality and yield remain unclear. According to our previous research, our project aims to focus on the functions of 2 miRNA (tae-miR5048 and tae-miR9663) which highly express in flag leaves. RNA degradom from wheat flag leaves will be deeply sequenced by high-throughput to determine the candidate target mRNAs of miRNA. The pre-miRNA sequences and the miRNA target genes will be cloned. The expression pattern of miRNAs and their targets will be examined. The biological functions of these two miRNAs and their target genes will be identified by two approaches, i.e. VIGS of wheat seed-specific gene expression and wheat transgenic overexpression.

miRNA是一类重要的调节内源基因表达的调控因子，广泛参与植物的生长发育。旗叶对小麦生殖器官的发育及小麦产量有极为重要的作用。最近，我们在小偃6号小麦中鉴定出旗叶偏爱性高表达miRNA，它们如何调控旗叶的生长发育及小麦品质产量尚不清楚。在前期研究的基础上，本项目重点研究2个小麦旗叶偏爱性高表达的新miRNA（tae-miR5048和tae-miR9663）的功能。拟对旗叶的RNA降解组进行高通量测序，确定候选miRNA的靶基因；分离克隆miRNA及其靶基因序列；实验验证miRNA及其靶基因的表达模式；利用病毒诱导小麦旗叶內源基因沉默和转基因过表达进行候选miRNA和靶基因的功能鉴定。本项目将揭示候选miRNA对旗叶生长发育的调控作用及调控方式，并希望能鉴定出在小麦优质高产育种上具有应用价值的miRNA或靶基因。

miRNA参与调控植物生长发育、生物或非生物胁迫等多种生物学过程，并发挥重要作用。近年来，通过高通量测序已鉴定筛选出大量的小麦miRNA，但其生物学功能是未知的。tae-miR9663和tae-miR5062是本实验室前期鉴定出的新miRNA，它们在小麦幼苗、旗叶和发育的籽粒中都表达，尤其在旗叶中高表达。本项目首先鉴定并验证这两个miRNA的靶基因分别是TaFTIP1和TaAGO2。然后揭示了这两个靶基因在小麦各组织中均表达，但TaFTIP1主要在幼穗和籽粒里高表达，而TaAGO2主要在旗叶里表达。最后利用BSMV-VIGS技术和转拟南芥植株研究这两个miNA的功能，结果表明植株部分叶片的形态并使籽粒稍变大。本研究为小麦遗传改良育种奠定基础。