大麦光周期反应基因克隆及基因间互作研究

Heading date is a major determinant of the regional and seasonal adaptation of barley varieties, and genetically controllyed by vernalization, photoperiod and earliness per se. Locus Phd-H1 is the first gene identified and cloned, which related to the long photopheriod response. Qpho.BM.4-13 is the second long photoperiod sensitivity locus reported by us recently. Using two parents that carry Qpho.BM.4-13 and Ppd-H1 gene, respectively, we newly built one DH population containing 140 lines. We plan to screen the polymorphic molecular markers, construct genetic linkage map, collect the photoperiod phenotypic data, and then further map the Qpho.BM.4-13 and analyze the espistatic effect between the two genes. Meanwhile, on the basis of Qpho.BM.4-13 near isogenic lines (NILs) that we have built, high-density SNP map will be built together with the strategies of comparative genomics, bioinformatics, minimum tiling path (MTP) BACs will be built with the aid of the international barley genome project,the MTP BACs will be sequenced using genome-wide transcriptomes of NILs under controlled lighting conditions, the candidate genes will be predicted,transformation-competent artificial chromosome (TAC) libarary will be constructed using parent Baudin that carries the photoperiod sensetive allele on 4H, and transformation in Arabidopsis thaliana using the candidate TAC clones will be performed to functionally verify the new gene finally.Results from this study will be helpful to clarify the molecular mechanisms of the new gene underlying the photoperiod response, to provide the technological support for the molecular breeding for maturity in barley, to give hints for the adjustment of the planting pattern of multiple crops per year.

抽穗期是决定大麦种植区域和季节适应性的重要因素，遗传上受春化反应、光周期反应和早熟性三大因素控制。Ppd-H1是第一个发现并被克隆的控制大麦长日照光周期反应基因，Qpho.BM.4-13是我们新近定位报道的第二个同类型基因。利用分别携带这两个基因的亲本材料，构建了DH系群体，拟在此基础上进一步定位Qpho.BM.4-13，并分析这两个光周期反应基因间互作关系；同时，在我们已构建的近等基因系(NILs)基础上，拟综合运用比较基因组学、生物信息学等方法，构建高密度SNP图谱；利用国际大麦基因组测序计划，构建最少覆盖(MTP)BACs，利用NILs在可控光照条件下全基因组转录物组对MTP BACs测序并进行候选基因预测，构建TAC文库，用候选TAC克隆转化拟南芥，并功能验证，确认候选基因。研究结果有助于阐明新基因光周期反应分子机理，为大麦熟期分子育种提供依据，为一年多茬作物种植模式调整提供参考。

围绕着大麦光周期反应基因的克隆及基因间互作关系，构建Chebec/Baudin的DH群体，通正常光照及延长光照处，初步鉴定了Qpho.BM.4-13 和Ppd-H1间的互作关系，结果说明来自Baudin的Qpho.BM.4-13可以作为大麦抽穗期改良的一个新的光周期基因位点。采用RAD-seq技术，共开发23000个分子标记，其中19998个标记整合到大麦染色体上，构建了Baudin/AC Metcalfe DH群体的超高密度遗传连锁图谱，加密了大麦遗传连锁图谱。利用大麦表型和基因型集成生物信息系统（Phenotype and Genome Integration System, PGIS），预测大麦HvFt5基因可能是Qpho.BM.4-13基因的候选基因，比较了该基因在不同地区大麦品种中的单倍型差异，开发了该基因的分子诊断标记。