PMeS-1基因与光敏核不育基因pms3结合在多倍体水稻雄性不育系选育中的关键作用

Many breakthroughs were made in research of two-line hybrid rice recently. After the photoperiod-sensitive nuclear gene pms3 was cloned in nuclear male sterile line N58S, gene p/tms12-1 was cloned in thermo-sensitive male sterile line PA64S the other day. This gene is a noncoding gene, but it had expression difference of photoperiod- and thermo-sensitive in different genetic background of japonica and indica. Then, whether the pms3 gene had difference of gene dosage or promoter regulation after polyploidization? How does the PMeS-1 gene that can raise the seed set rate of polyploid rice assure the sterile lines fertility transformation under suitable photoperiod and temperture condition? These are key problems in breeding of polyploid rice sterile lines. In this research, the PMeS gene line will be used as the key material. The regulation difference of pms3 or p/tms12-1 in diploid and polyploid male sterile lines, the mechanism of PMeS gene line how to stabilize meiosis and assure normal development of floral organs and pollens to get stable sterility and normal fertility transformation of polyploid sterile lines will be studied. Moreover, elite male sterile lines with the characters of multiple resistance and stable sterility will be bred through molecular markers-assisted selection and polymerization of multiple resistance. This research will explore a new parthway for heterosis utilization in rice.

最近两系杂交稻研究取得突破性进展。光敏核不育基因pms3克隆成功后，同一基因在温敏核不育系PA64S中克隆成功（p/tms12-1）。它是一个非编码基因，但在粳、籼不同背景下表现出光敏和温敏的差异性。那么，多倍体化后pms3基因是否具有基因剂量效应或启动子调控差异呢？我们发现的提高多倍体水稻结实率的PMeS-1基因如何保证不育系在适宜温光条件下发生育性转换而结实呢？这是多倍体水稻不育系选育的核心问题。本项目以PMeS基因品系为核心，研究多倍体雄性不育系与二倍体雄性不育系的pms3或p/tms12-1的调控作用差异；PMeS基因品系发挥稳定减数分裂，保证花器和花粉正常发育对于保证不育的稳定性和育性正常转换的关键作用；通过分子标记辅选与多抗聚合相结合选育出多抗、不育性稳定、转育结实好的优良多倍体不育系，为水稻杂种优势利用探索新途径。

为解决世界粮食危机，需要新的大幅增产的新思路、新技术。“利用远缘杂交和多倍体双重优势选育超级稻”是继高秆变矮秆、常规稻变杂交稻之后，二倍体稻变多倍体稻的新一次绿色革命。借鉴主要作物小麦、棉花、油菜由二倍体野生种演化成多倍体栽培种后产量成倍增加的自然启示，开展多倍体水稻研发选育出增产20~30%的新品种最有可能。根据基金计划安排，本项目首先重点构建合适的材料体系，通过组培与秋水仙素处理结合诱导典型光温敏雄性核不育水稻品系农垦58S（粳稻）、培矮64S（籼稻）、HD9802S（籼稻，温敏型）的二倍体加倍形成各自四倍体，并与此前获得的光温敏雄性不育性和高结实率特性的WS006-2x、-4x，WS012-2x、-4x（具PMeS基因）一起构成四种不同类型、不同倍性的光温敏雄性核不育基因不育系的材料体系，有利于进行不育稳定性和育性转换研究。其后，利用上述材料体系，对2x、4x品系进行形态特征、开花习性和花粉育性特点比较，发现2x条件下，各雄性不育系都具有规律性，即在长日高温和短日低温条件下不育、可育及不育向可育、可育向不育转换的特点；在4x条件下，农垦58S-4x、培矮64S-4x、HD9802S-4x、WS006-4x和WS012-4x的花药都明显比2x大，农垦58S-4x、培矮64S-4x、HD9802S-4x的不育比二倍体更厉害，套袋结实率0~0.15%，但不育向可育转换不彻底。而具有高结实PMeS基因的WS006-4x和WS012-4x的不育期不育彻底，转换期可育也很明显，不育时套袋结实率0~0.05%，可育时结实率可达67~72%。后两个品系的4x、2x均可在海南冬春季繁殖，在武汉不育并制种，可以应用于生产实践。为此我们申请了相关的多倍体水稻光温敏雄性核不育系、恢复系及其杂种配制的3个发明专利和构建PMeS近等基因系的发明专利；并且获得3项发明专利授权；正申请湖北省地方标准1项，申请国家品种保护权2个，发表英文论文6篇（其中SCI论文4篇）。通过农垦58S-4x、2x和具PMeS基因的光温敏雄性核不育系的pms3及p/tms12-1基因的启动子区域比较发现2x、4x并无差异，说明4x不育系可稳定。它们与PMeS高结实性相结合可应用于多倍体杂交稻实践。但PMeS保障光温敏雄性不育系的可育性机理研究不够。