Fine Mapping and Gene Analysis of restorer-of-fertility Gene CaRf(HZ) in Pepper (Capsicum annuum L.)

Cytoplasmic male sterility (CMS) is a common biological phenomenon used in hybrid production of peppers (Capsicum annuum L.). Although several restorer-of-fertility (Rf) genes of pepper CMS lines have been mapped, there is no report that the Rf gene with clear gene function has been isolated. Here, pepper CMS line HZ1A and its restorer line HZ1C were used to construct (HZ1A × HZ1C) F(2) populations and map the Rf gene. A single dominant gene CaRfHZ conferred male fertility according to inheritance analysis. Using sterile plants from (HZ1A × HZ1C) F(2) populations and bulked segregant analysis (BSA), the CaRf(HZ) gene was mapped between P06gInDel-66 and P06gInDel-89 on chromosome 6. This region spans 533.81 kb, where four genes are annotated according to Zunla-1 V2.0 gene models. Based on the analysis of genomic DNA sequences, gene expressions, and protein structures, Capana06g002968 was proposed as the strongest candidate for the CaRf(HZ) gene. Our results may help with hybrid pepper breeding and to elucidate the mechanism of male fertility restoration in peppers.