水稻灌浆期耐夜间高温的基因转录调控网络研究

Breeding rice new cultivar with night heat-tolerant characters is a basic countermeasure to response to the climate change. In our previous study, we bred a pair of rice lines with significant different heat-tolerant characters at milky stage, heat-tolerant rice XN0437T and heat-sensitive rice XN0437S. According to the actual conditions that high climate temperature harms the double-season early rice in China, and to the main reason that high night temperature is the direct factor decreasing rice yield, this project is to construct and compare the gene transcript regulatory networks of heat-tolerant and heat-sensitive rice at milky stage responding to high night temperature. This study aims to find the key genes of rice responding to high night temperature and provides effective molecular markers and novel genes for heat-tolerant rice cultivar breeding. The study also aims to construct the gene transcript regulatory networks of heat-tolerant characters in rice and provides a base on research the molecular mechanism. The project is very important, on accelerating the process of breeding and application in new rice cultivars with high night tolerant characters at milky stage, and on the food safety in China.

培育灌浆期对夜温升高钝感的水稻新品种，是应对气候变化的根本性对策。前期研究中，本项目组已育成了一对灌浆期耐热性差异极显著的近等基因系耐热纯系XN037T和热敏感纯系XN037S。根据高温气候危害我国双季早稻灌浆的实际情况以及灌浆期夜间高温是直接导致水稻减产的主要原因，本项目从转录水平着手，建立和比较耐热纯系和热敏感纯系应答灌浆期夜间高温的基因转录调控网络，挖掘水稻耐夜间高温的转录调控关键基因，确立水稻灌浆期耐夜间高温的基因转录调控网络，从而为培育灌浆期对夜温升高钝感的水稻新品种提供有效的分子标记和基因元件，为进一步揭示水稻灌浆期耐热的分子调控机制研究奠定基础。这对加快选育、推广应用灌浆期对夜温升高钝感的水稻优良新品种，进而保障国家的粮食安全具有重要意义。

全球气候变暖、短期的夏季高温频繁影响作物的产量和品质。水稻灌浆前期是高温热害的敏感期之一，此时遭遇高温热害既造成单位面积减产，也导致稻米品质变劣，而且水稻耐热性存在极显著的基因型差异。研究表明，夜间高温阻碍水稻籽粒灌浆充实，导致籽粒粒重下降，最终造成减产，是直接导致水稻减产的主要气候因子。双季早稻是我国重要的一茬粮食作物，也是南方各省不可替代的优势粮食作物。因而，加快选育、推广应用灌浆期对夜温升高钝感的水稻新品种，是应对气候变化的根本性对策，对保持我国水稻产量和品质的稳定，进而保障国家的粮食安全具有重要意义。前期研究中，本项目组已育成了一对灌浆期耐热性差异极显著的近等基因系耐热纯系XN037T和热敏感纯系XN037S。根据高温气候危害我国双季早稻灌浆的实际情况以及灌浆期夜间高温是直接导致水稻减产的主要原因，本项目分别通过RNA-seq和iTRAQ技术分别分析了耐热和热敏感水稻应答灌浆期夜间高温的基因转录网络和蛋白互作网络。并从基因调控网络中选择了2个可能是调控水稻灌浆期耐热性的关键基因TCONS_00032475和TCONS_0003660、通过构建过表达载体并转化水稻，验证了这些基因的功能。这两个基因导入水稻后，夜间高温胁迫下，转TCONS_00032475基因水稻可导致水稻单株产量少减产14.7%，转TCONS_0003660基因水稻可导致水稻单株产量少减产15.6%。