OsPSK5调控水稻种子活力及其分子机制

基于在前期研究中发现水稻PSK5基因(OsPSK5)是种子活力调控因子miR164c的靶基因，其表达水平受miR164c的负调控，且与种子活力呈正相关性；OsPSK5的翻译产物可加工形成短肽类植物生长物质─植物磺肽素(PSK)。PSK在高等植物中普遍存在，具有促进细胞生长和增殖，促进组织分化和增强植物的逆境胁迫耐性等广泛的生理功能；因此推测OsPSK5通过PSK的信号转导途径参与种子活力的调控。本项目试图：(1)通过OsPSK5的过表达和CRISPR/Cas9基因敲除两类水稻突变体，验证水稻种子中OsPSK5的表达水平与PSK含量和种子活力的关系；(2)通过酵母双杂交技术筛选和鉴定水稻的PSK受体(OsPSKR)的互作蛋白及其下游互作蛋白，并借助外源PSK验证OsPSKR的信号转导途径，从而揭示OsPSK5调控种子活力的分子机制，并为改良水稻种子活力提供新的分子育种途径。

In the previous study, OsPSK5 was found to be a target gene of miR164c, its expression level was negatively regulated by miR164c and positively correlated with rice seed vigor. It is well known that the translation product of OsPSK5 can be processed to generate Phytosulfokine (PSK). PSK belongs to the group of plant peptide growth factors, ubiquitously presents in higher plants, plays universal functions, including promoting cell growth and proliferation, contributing to tissue differentiation, and enhancing plant's stress tolerance etc. It is suggested that through the signal transduction pathway of PSK, OsPSK5 play a role in regulating seed vigor, however the underlying molecular mechanism is unclear. The present study attempt to: (1) using rice mutants of over-expression and CRISPR/Cas9 knock-out of OsPSK5, verify the correlation between the expression level of OsPSK5, PSK content and seed vigor; (2) by means of yeast two-hybrid system, screen out and identify the interacting proteins of the receptor of PSK in rice (OsPSKR) and the downstream interacting proteins, and via exogenous PSK validate the signal transduction pathway of OsPSKR, in order to uncover the molecular mechanism of OsPSK5 regulating on seed vigor and provide a new molecular breeding pathway to improve rice seed vigor.