匍匐翦股颖miRNA介导的高温响应基因调控网络研究

High temperature in summer season is one of the major abiotic stresses for cool-season turf grasses. Exploring plant heat resistance has become a key research topic. Currently, the most reports were concentrated in the field of physiology and ecology but less concern in molecular mechanism. In the previous study, the applicant had screened out a high resistant creeping bentgrass variety against heat stress. Some heat responding genes were identified via differential gene expression analysis. For well understanding the molecular mechanism to heat in turf grass, the project here supposes to conduct whole length transcript sequencing to consummate the detailed gene information responding to heat stress in creeping bentgrass. The miRNAs regulating the gene expression will be identified via small RNA sequencing technology. The regulation network of heat resistance genes mediated by miRNAs would be constructed finally through joint analysis. The research results might reveal the characteristics of creeping bentgrass against heat stress and improve the gene regulation system mediated by miRNA that is significant to dissect the resistant molecular mechanism of plants to heat. Also, it would build an important platform for the gene function analysis and molecular breeding program in future.

夏季高温是影响冷季型草坪草景观效应的主要逆境之一，高温抗性已成为其研究的热点。目前相关的报道主要集中于生理生态方面，分子机制的研究较为缺乏。申请人在前期研究中，筛选出一个抗热的匍匐翦股颖品种，通过基因表达差异分析获得了高温响应基因的信息。为系统探讨草坪草抗热的分子机制，本项目拟通过全长转录组测序，完善匍匐翦股颖草坪草高温响应基因的信息；依据小RNA测序，鉴定调控基因表达的miRNAs；通过联合分析，建立草坪草miRNA介导的高温响应基因调控网络。研究结果将揭示匍匐翦股颖草坪草高温响应的特点，完善miRNA介导的高温响应基因调控体系，促进草坪草高温抗性分子机理的解析，为深入的基因功能研究及分子育种工作搭建重要的平台。

夏季高温是影响冷季型草坪草景观效应的主要逆境之一，高温抗性已成为其研究的热点。本研究以耐热匍匐翦股颖草坪草品种为材料，通过高通量小RNA测序技术，鉴定了高温处理前后表达量存在显著性差异的560个miRNA，其中261个miRNA表达上调，299个表达下调；高温响应miRNAs的靶基因主要涉及12条代谢通路，包括植物激素信号转导、植物与病原物交互作用等，构建了匍匐翦股颖miRNA抗热基因的表达调控网络；克隆了抗热相关的miRNA171及其靶基因，通过转化烟草，验证了miRNA171的抗热功能；通过5’-RACE技术，发现miRNA171对不同靶基因的切割位点存在差异，推测由于基因结构差异所致；通过瞬时转化技术，分析了miRNA171对不同靶基因的抑制效率，发现靶基因配对位点的碱基变化以及基因结构的变化影响了miRNA171与靶基因的互作。研究结果揭示了匍匐翦股颖草坪草高温响应的特点，完善了草坪草高温抗性的理论体系；构建了miRNA介导的高温响应基因调控网络，促进了草坪草高温抗性机理的解析；丰富完善了miRNA对靶基因的调控过程，为深入解析miRNA的作用奠定了基础；鉴定的抗热miRNA，也为冷季型草坪草抗热分子育种工作提供了有效的基因资源。