新型四倍体水稻（neo-tetraploid rice）基因组变异及高育性分子遗传

High yield potential has been found in autotetraploid rice and the hybrids of indica and japonica autotetraploid rice; however, low fertility of F1 is a major barrier for commercial utilization. Therefore, it is very important to develop new lines with high pollen and embryo sac fertility that affect mainly fertility of autotetraploid rice. The neo-tetraploid rice with high fertility had been developed in our lab. In this project, the research will be carried out using neo-tetraploid rice as follows: (1) Study on genomic variation of 5 neo-tetraploid rice using re-sequencing;(2)Comparative study on transcriptomes of pollen and embryo sac mother cell in prophase stage I of meiosis between high and low fertility directional lines developed using neo-tetraploid rice crossed with an autotetraploid rice with low fertility; (3) Co-analysis on transcriptomes and re-sequencing data, and gene functional verification by qRT-PCR will be done finally. These studies are planned to find the genes assocaited with high fertilty of neo-tetraploid rice,which are helpful in cloning the gene and explainning the molecular mechanism of high fertility.

同源四倍体水稻及其亚种间杂种F1具有明显增产潜力.但其结实率普遍偏低,难以直接应用.花粉和胚囊育性是决定其结实率最主要的2个因素,培育两者都高的四倍体水稻新种质具有重要意义.申请者在杂交F5发现高育性变异株并由此培育出两者育性均高的新型四倍体水稻(Neo-tetraploid rice),为开展高育性遗传研究及育种提供材料.本项目拟利用该新材料开展3方面研究:一是利用5份新型四倍体水稻及双亲,通过高通量测序技术比较研究新材料基因组变异;二是利用其中1份新材料与低育性同源四倍体水稻杂交创建的高和低育性新定向自交系群体构建高低育性的混合池,通过高通量转录组测序分别比较研究两者花粉和胚囊减数分裂前期I表达谱差异,找出与高育性相关的差异表达基因;三是通过基因组和转录组结果的综合分析,以及差异基因功能验证分析,弄清决定高育性相关的遗传基因及可能的分子机理,为进一步开展其基因克隆和育种应用提供基础.

新型四倍体水稻是我们创制的高育性四倍体水稻，具有利用前景。本项目围绕新型四倍体水稻可能存在基因组新变异以及高育性涉及的分子遗传，利用5份新型四倍体水稻及育性定向自交系群体为材料，开展比较基因组和遗传学功能分析等研究，取得以下结果：（1）新型四倍体水稻基因组DNA存在丰富的变异，发现222个非亲本型的特异变异基因，以及1个目前在二倍体水稻中未发现的新变异基因。（2）利用高和低育性定向自交系群体构建混合池，通过高通量测序比较研究，筛选到与育性相关的染色体片段，即7号染色体18915234-19500000的区段。（3）通过基因组和转录组结果的综合分析,以及基因敲除验证，发现包括NRFG1在内的9个基因可能与育性有关。目前正进行互补和进一步的分子机理研究。以上结果为进一步开展其基因的克隆和育种应用提供基础. 项目完成期间，已正式发表SCI收录论文8篇，其中有1篇为农林科学大类分区1区；2份新型四倍体水稻获得国家植物新品种权；培养3名博士和6名硕士。