Abstract：
In soybean, heterosis achieved through the three-line system has been gradually applied in breeding to increase yield, but the underlying molecular mechanism remains unknown. We conducted a genetic analysis using the pollen fertility of offspring of the cross NJCMS1A×NJCMS1C. All the pollen of F1 plants was semi-sterile; in F2, the ratio of pollen-fertile plants to pollen-semi-sterile plants was 208:189. This result indicates that NJCMS1A is gametophyte sterile, and the fertility restoration of NJCMS1C to NJCMS1A is a quality trait controlled by a single gene locus. Using bulked segregant analysis, the fertility restorer gene Rf in NJCMS1C was located on chromosome 16 between the markers BARCSOYSSR_16_1067 and BARCSOYSSR_16_1078. Sequence analysis of genes in that region showed that GmPPR576 was non-functional in rf cultivars. GmPPR576 has one functional allele in Rf cultivars but three non-functional alleles in rf cultivars. Phylogenetic analysis showed that the GmPPR576 locus evolved rapidly with the presence of male-sterile cytoplasm. GmPPR576 belongs to the RFL fertility restorer gene family and is targeted to the mitochondria. GmPPR576 was knocked out in soybean N8855 using CRISPR/Cas9. The T1 plants showed sterile pollen, and T2 plants produced few pods at maturity. The results indicate that GmPPR576 is the fertility restorer gene of NJCMS1A.
摘要：
在大豆中，通过三系系统实现的杂种优势已逐步应用于育种中以提高产量，但是潜在的分子机制仍然未知。我们使用NJCMS1A×NJCMS1C杂交后代的花粉育性进行了遗传分析。F1植物的所有花粉都是半不育的；在F2中，花粉可育植物与花粉半不育植物的比例为208：189。此结果表明NJCMS1A是配子体不育，NJCMS1C对NJCMS1A的育性恢复是由单个基因位点控制的品质性状。使用大量的分离分析，NJCMS1C中的育性恢复基因Rf位于标记BARCSOYSSR_16_1067和BARCSOYSSR_16_1078之间的16号染色体上。该区域基因的序列分析表明GmPPR576在rf品种中没有功能。GmPPR576在Rf品种中具有一个功能性等位基因，而在rf品种中具有三个非功能性等位基因。系统发育分析表明，GmPPR576基因座在雄性不育细胞质的存在下迅速进化。GmPPR576属于RFL育性恢复基因家族，靶向线粒体。使用CRISPR/Cas9在大豆N8855中敲除GmPPR576。T1植株表现出不育花粉，T2植物在成熟时产生很少的豆荚。结果表明，GmPPR576是NJCMS1A的育性恢复基因。
