小麦渐渗系SR3耐盐主效基因Tasro1调控ATP代谢的机制

Soil salinization seriously restricts grain production, and thus it is of great significance to breed salt-tolerant crop varieties and to analyze their mechanisms for salt tolerance. Coordinating energy balance between stress tolerance and development is important for crop genetic improvement, which is still limited by breakthroughs in theoretical research. Shanrong NO. 3 (SR3), was bred in our laboratory as a high-yielding wheat cultivar with strong salt tolerance and vigorous growth characteristics, and its major gene, Tasro1, could promote both salt tolerance and growth. It has been revealed that Tasro1 improves salt tolerance via modulating redox homeostasis. However, the mechanism of Tasro1 for regulating growth (take the leaf as a model) is still unclear. Based on the phenomenon that Tasro1 mediates the increase of leave size and the decrease of ATP level in SR3, the applicant found the Tasro1 interacting protein TaSIN was associated with these phenotypes, and TaBCS1b, a target gene of TaSIN, was found to play an important role in ATP metabolic pathway. TaSIN-TaBCS1b increased ATP content while inhibited the development of wheat leaves, which suggested that Tasro1 might regulate leaf development via ATP metabolism. On this basis, our project aims to elucidate the mechanism of Tasro1 regulating TaBCS1b via TaSIN, to reveal the role of TaBCS1b in regulating ATP metabolism as well as leaf development, which will provide clues for further understanding the mechanism of balancing stress tolerance and development of SR3, and helpful for breeding new wheat cultivars with high yield and stress tolerance.

土地盐渍化严重制约粮食生产；创建作物耐盐品种，解析其耐盐机制意义重大。协调耐逆与发育的能量分配是作物育种的重要任务，目前仍受限于理论突破。本实验室创建小麦高产耐逆渐渗系SR3，鉴定到主效基因Tasro1同时促进耐盐与生长，并已揭示Tasro1通过调控ROS稳态促使SR3耐盐，但有关生长发育（以叶为例）的调控机制仍未探明。基于Tasro1导致叶片增大而ATP减少，申请人发现该表型与Tasro1互作蛋白TaSIN有关，且TaSIN靶基因TaBCS1b是调控ATP代谢的节点；TaSIN-TaBCS1b提高ATP含量而抑制叶片生长。由此提出Tasro1影响ATP代谢而调控叶片发育的假说。本项目拟阐明Tasro1通过TaSIN调控TaBCS1b的机理；揭示TaBCS1b对ATP代谢和叶片发育的调控机制，为进一步解析SR3协调耐逆与发育的机理，开创小麦高产耐逆育种新途径提供理论基础及实践思路。

土地盐渍广泛制约着粮食生产，培育抗盐品种，协调耐逆与发育是作物育种的重要任务。项目负责人团队前期培育得小麦高产耐逆渐渗系SR3，并发现Tasro1是调控耐逆与发育的焦点基因，Tasro1可以调控ROS稳态促使SR3耐盐。然而，关于Tasro1如何调控发育尚不明确。本研究基于Tasro1促使叶片增大而ATP减少的现象，发现该效应可能与Tasro1互作蛋白TaSIN及其下游基因TaBCS1有关，由此聚焦研究Tasro1-TaSIN-TaBCS1调控ATP代谢和叶片生长的机制。本研究发现，TaSIN通过结合TaBCS1启动子激活后者转录，而Tasro1可以通过互作抑制TaSIN的转录激活效应；TaBCS1定位于线粒体，可能参与呼吸链复合物的调控；TaBCS1与线粒体蛋白TaLETM2直接互作，且两者对叶片生长和ATP代谢的影响相反；TaSIN-TaBCS1能够调控叶绿体淀粉粒代谢，且该通路调控下ATP代谢与淀粉积累正相关，暗示线粒体与叶绿体存在功能相关性；TaSIN-TaBCS1参与调控细胞周期，并影响叶细胞多倍体化;TaBCS1在小麦中存在诸多同源基因，功能具有冗余性。由此，本研究揭示了Tasro1-TaSIN-TaBCS1-TaLETM2通路在调控小麦叶片发育和能量代谢中的作用，阐述了Tasro1调控叶片发育的机制，为理解耐逆与发育的协同调控机制提供了参考；明确了TaBCS1调控下能量代谢与发育调控的相关性，阐述了TaSIN-TaBCS1通过能量代谢平衡及多倍体化影响叶片生长的具体机理，为作物育种提供了新思路；发现了TaBCS1与TaLETM2互作并影响线粒体功能，为进一步详细分析TaBCS1调控ATP代谢的具体机制奠定了基础。此外，本研究还发掘出关于线粒体与叶绿体的功能协调、小麦BCS1-like蛋白的功能分化等新问题，可以为后续研究提供有意义的指导。