Genetic Analysis of <i>S5</i> Regulating the Hybrid Sterility between <i>Indica</i> and <i>Japonica</i> Subspecies in Rice
Jie Guo,
Xinqiao Zhou,
Ke Chen,
Chanjuan Ye,
Juan Liu,
Kangli Sun,
Guang Tang,
Shaokui Wang,
Guiquan Zhang,
Youding Chen,
Dagang Chen,
Chuanguang Liu
Affiliations
Jie Guo
Key Laboratory of Genetics and Breeding of High Quality Rice in Southern China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
Xinqiao Zhou
Key Laboratory of Genetics and Breeding of High Quality Rice in Southern China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
Ke Chen
Key Laboratory of Genetics and Breeding of High Quality Rice in Southern China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
Chanjuan Ye
Key Laboratory of Genetics and Breeding of High Quality Rice in Southern China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
Juan Liu
Key Laboratory of Genetics and Breeding of High Quality Rice in Southern China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
Kangli Sun
Guangdong Provincial Key Laboratory of Plant Molecular Breeding, South China Agricultural University, Guangzhou 510640, China
Guang Tang
Guangdong Provincial Key Laboratory of Plant Molecular Breeding, South China Agricultural University, Guangzhou 510640, China
Shaokui Wang
Guangdong Provincial Key Laboratory of Plant Molecular Breeding, South China Agricultural University, Guangzhou 510640, China
Guiquan Zhang
Guangdong Provincial Key Laboratory of Plant Molecular Breeding, South China Agricultural University, Guangzhou 510640, China
Youding Chen
Key Laboratory of Genetics and Breeding of High Quality Rice in Southern China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
Dagang Chen
Key Laboratory of Genetics and Breeding of High Quality Rice in Southern China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
Chuanguang Liu
Key Laboratory of Genetics and Breeding of High Quality Rice in Southern China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
Hybrid sterility is the major obstacle to the utilization of inter-subspecific heterosis in hybrid rice breeding. The S5 locus, composed of three adjacent genes ORF3, ORF4, and ORF5, plays a crucial role in regulating indica/japonica hybrids’ female sterility. Through a series of crosses involving 38 parents, three alleles of S5, ORF3+ORF4−ORF5n, ORF3+ORF4+ORF5n, and ORF3−/ORF4−/ORF5n, all could be regarded as wide-compatibility alleles, and when crossed with indica or japonica rice, they all showed significantly high fertility. Then, in order to explore the genes’ function, we further knocked out genes by using CRISPR/Cas9-based genome editing. Our results demonstrate that the ORF3+ was not just the protector in the killer-protector system, and knocking out ORF3 of the indica allele seriously affected the rice’s normal development. We observed the concrete enhancing hybrid spikelet fertility from the crosses between the ORF4+ knockout japonica materials with indica varieties. By conducting the comparative RNA-Seq analysis of young spikelets, we found that the ORF4+/ORF4− could modulate the hybrid fertility by affecting the expressions of genes related to the function of the Golgi apparatus. This study indicated that knocking out the ORF4+ of the japonica allele or using the alleles carrying ORF5n would provide effective approaches to overcome indica/japonica hybrid female sterility in rice breeding.
