NtMYB305和NtbHLH8互作调控烟草花药壁淀粉代谢的分子机制

Pollen fertility is a key factor affecting the seed formation of flowering plants and grain yield of crops, and has always been a hot topic in botany. Jasmonates display important roles in the regulation of pollen fertility, and its effects are dependent on the regulatory actions of the COI1-JAZ receptor complex on downstream transcription factors. We found previously that the regulation of pollen development by the jasmonate receptor protein COI1 is associated with starch metabolism in the anther wall during the microspore stage in tobacco, and the downstream transcription factor NtMYB305 and its co-factor NtbHLH8 are both involved in the regulation of starch metabolism in the anther wall. However, the molecular mechanisms by which these two factors co-regulate this process are unclear. On the basis of previous studies, this project will further investigate the transcription regulatory relationship between NtMYB305 and NtbHLH8, analysis the molecular interactions between NtMYB305 and NtbHLH8 in plants, identify crucial domains and amino acid sites for interactions, study the regulation of the expression of crucial genes involved in starch metabolism via NtMYB305 and NtbHLH8 interactions in the anther wall, and elucidate the molecular mechanisms by which these two factors co-regulate starch metabolism in the anther wall of tobacco. Our results will help in revealing the effector mechanisms by which the COI1 and jasmonate signalling pathways regulate anther wall starch metabolism and provide a theoretical basis for the regulation of pollen fertility in crop plants.

花粉育性是影响开花植物种子形成及农作物籽粒产量的关键因子，一直是植物学的研究热点。茉莉素在花粉育性调控中发挥重要作用，其作用依赖于COI1-JAZ受体复合体对其下游转录因子的调控功能。前期研究发现，烟草茉莉素受体蛋白COI1调控的花粉发育与小孢子期花药壁淀粉代谢相关，其下游转录因子NtMYB305及其互作因子NtbHLH8均参与了花药壁淀粉代谢调控过程，但二者互作调控该过程的分子机制仍不清楚。本项目将进一步研究NtMYB305与NtbHLH8之间的转录调控关系；解析NtMYB305和NtbHLH8在植物体内的分子互作关系，鉴定二者互作的关键结构域和氨基酸位点；研究NtMYB305和NtbHLH8互作对花药壁淀粉代谢关键基因的表达调控，阐明二者互作调控烟草花药壁淀粉代谢的分子机制。研究结果有助于揭示COI1及茉莉素信号途径调控花药壁淀粉代谢的作用机制，为作物花粉育性调控提供理论基础。

花粉育性是影响开花植物种子形成及农作物籽粒产量的关键因子，一直是植物学的研究热点。茉莉素在花粉育性调控中发挥重要作用，其作用依赖于COI1-JAZ受体复合体对其下游转录因子的调控功能。前期研究发现，烟草茉莉素受体蛋白COI1调控的花粉发育与小孢子期花药壁淀粉代谢相关，其下游转录因子NtMYB305及其互作因子NtbHLH8(即NtMYC2a)均参与了花药壁淀粉代谢调控过程，但二者互作调控该过程的分子机制仍不清楚。本项目鉴定了花药壁淀粉代谢调控因子NtMYB305的互作蛋白NtbHLH8，分析了NtMYB305与NtbHLH8互作的生化及分子机制，证明NtMYB05和NtbHLH8均参与了花粉育性及花药壁淀粉代谢调控；解析了NtMYB305与NtbHLH8之间的转录调控关系以及NtMYB305调控花药壁淀粉代谢基因的分子基础；通过遗传分析材料培育进行了NtMYB05和NtbHLH8调控花药壁淀粉代谢的遗传研究，分析了NtMYB05和NtbHLH8对花药壁淀粉代谢基因的表达调控，发现NtbHLH8调控烟草花粉和子房中的淀粉积累以及花发育过程中淀粉代谢相关基因的表达。研究结果有助于揭示COI1及茉莉素信号途径调控花药壁淀粉代谢的作用机制，为作物花粉育性调控提供理论基础。