水稻miR408耐冷功能与作用机制研究

Low temperature has always been one of the major disastrous climates in influencing crop yields. miR408 has been known to be a pivotal regulator in plant development and stress response. However, little is known about its function in regulating cold tolerance in rice. In previous studies we found that AK101374, a gene encoding miR408 precursor , was up-regulated under cold stress in several rice varieties by microarray analysis. Overexpressing miR408 could enhance cold tolerance in ZH11 species. We speculate that miR408 played important roles in cold tolerance in rice. Based on these studies, this project aims to carry out the following researches: (1) Function of miR408 is studied by evaluating Cold tolerance of miR408 overexpression plants as well as down-regulated ones and analyzing correlation of cold tolerance and miR408 expression levels among different rice species. (2) Biological function of miR408 target genes is studied by using a combination of means such as reverse genetics, subcellular localization, detection of copper distribution, correlation analysis of metabolites and transcripts. Upon these studies mechanism of miR408-mediated cold tolerance in rice is to be elucidated. The implementation and completion of this project not only improve our understanding how miR408 interacts with cold stress, but also lay the foundation for rice molecular breeding in cold tolerance.

低温冷害一直以来都是影响农作物生产的主要灾害性气候之一。miR408是植物生长及抵抗环境胁迫的重要调节子，但是有关其在水稻耐冷性方面功能的研究较少。我们前期从多份水稻对低温反应的表达谱芯片中发现，编码miR408前体的基因AK101374受低温诱导明显上调表达，过量表达miR408能提高水稻耐冷能力，推测miR408在水稻耐冷过程中起着重要的作用。在此基础上，本项目拟开展以下研究：(1)通过对miR408过量表达和抑制表达植株进行耐冷评价以及品种间miR408表达量与耐冷性相关性分析，研究miR408耐冷功能；(2)通过反向遗传学、亚细胞定位、铜的含量测定等综合手段研究miR408靶基因的生物学功能，结合代谢组与转录水平相关性分析，阐明miR408介导的耐冷作用机制。该项目的实施和完成不仅可以加深人们对miR408与低温胁迫互作的认识，而且可以应用于水稻耐冷分子育种。