Fine Mapping and Transcriptome Analysis Reveal Candidate Genes Associated with Hybrid Lethality in Cabbage (Brassica Oleracea).

Hybrid lethality is a deleterious phenotype that is vital to species evolution. We previously reported hybrid lethality in cabbage () and performed preliminary mapping of related genes. In the present study, the fine mapping of hybrid lethal genes revealed that was located on chromosome C1 between BoHLTO124 and BoHLTO130, with an interval of 101 kb. was confirmed to be between insertion-deletion (InDels) markers HL234 and HL235 on C4, with a marker interval of 70 kb. Twenty-eight and nine annotated genes were found within the two intervals of and , respectively. We also applied RNA-Seq to analyze hybrid lethality in cabbage. In the region of , seven differentially expressed genes (DEGs) and five resistance (R)-related genes (two in common, i.e., and ) were found, whereas in the region of , two DEGs and four R-related genes (two in common, i.e., and ) were found. Along with studies in which R genes were frequently involved in hybrid lethality in other plants, these interesting R-DEGs may be good candidates associated with hybrid lethality. We also used SNP/InDel analyses and quantitative real-time PCR to confirm the results. This work provides new insight into the mechanisms of hybrid lethality in cabbage.