Sequencing of S5 gene in autotetraploid rice japonica and indica to overcome F1 hybrids embryo sac sterility

Abstract

Autotetraploid rice is a new germplasm developed through diploid chromosome doubling. Hybrids developed by indica autotetraploid rice crossed by japonica autotetraploid rice has clear biological advantage on F1, causing widespread concerns for special research evolution to evaluate and utilize F1 hybrid vigor. However, the widespread fertility of F1 indica and japonica autotetraploid rice is low, which makes it difficult to direct utilization of F1 vigor. In diploid indica and japonica rice, the fertility of F1 hybrids is also proved to be low. Embryo sac infertility is known to be one of the most important reasons for hybrid sterility and many studies has indicated that the primary cause of F1 sterility was abortion of the embryo sac, which was identified by the genotype of the S5 gene on the chromosome. Previous studies have cloned S5 based on common wild rice and cultivated rice and S5 sequence was obtained and studied. In this paper, typical sequence of different materials of S5 japonica and indica rice group of autotetraploid hybrids observed with whole-mount eosin B-staining confocal laser scanning microscopy WE-CLSM was utilized, to overcome F1 hybrids embryo sac sterility.   Key words: rice (Oryza sativa L.); autotetraploid; hybrid sterility; S5 gene; embryo sac fertility.