Cytological Observation and Candidate Gene Identification of a Female Semi-Sterile Rice Mutant

Abstract

Rice is an important staple crop, and fertilization has a very important role in the production of high-yield and well-quality hybrid of rice. The abnormal development of female gametes will lead to a significant decrease in rice yields. Due to the complex mechanism of female gamete development, the molecular mechanism of female sterility has not made a breakthrough. In this study, one semi-sterile mutant m21 and its fifth generation of backcross material (WZN58 and WZN68) were used as materials, and the phenotypic observation and cytological observation of embryo sac development were performed. Moreover, the pollen viability was evaluated by iodine potassium iodide (I2-KI) staining. Bulked-segregant analysis (BSA) re-sequencing and transgenic analysis were further applied to investigate the molecular mechanism of semi-sterile phenotype. These results demonstrated that male gamete development was normal, while the abnormality of the mutant was caused by the abnormal development of female gamete. Among 112 candidate genes detected by BSA, one gene Os10g0506000 was identified responsible for the semi-sterile phenotype of m21 mutant. This study provides an ideal material and candidate gene for rice female fertility analysis.