Genome-Wide Identification of the SPP/SPPL Gene Family and Regulating Male Fertility in Rapeseed ( L.).

Signal peptide peptidase (SPP) and its homologs, signal peptide peptidase-like (SPPL) proteases, are members of the GxGD-type aspartyl protease family, which is widespread in plants and animals and is a class of transmembrane proteins with significant biological functions. have been identified; however, the functions of SPP/SPPL in rapeseed ( L.) have not been reported. In this study, 26 were identified in rapeseed and categorized into three groups: SPP, SPPL2, and SPPL3. These members mainly contained the Peptidase_A22 and PA domains, which were distributed on 17 out of 19 chromosomes. Evolutionary analyses indicated that evolved with a large number of whole-genome duplication (WGD) events and strong purifying selection. Members are widely expressed and play a key role in the growth and development of rapeseed. The regulation of rapeseed pollen fertility by the gene was further validated through experiments based on bioinformatics analysis, concluding that silencing causes male sterility. Cytological observation showed that male infertility caused by loss of gene function occurs late in the mononucleate stage due to microspore dysplasia.