Fine Mapping and Identification of a Candidate Gene for the Glossy Green Trait in Cabbage (Brassica oleracea var. capitata)

In higher plants, cuticular wax deposited on the surface of epidermal cells plays an important role in protecting the plant from biotic and abiotic stresses; however, the molecular mechanism of cuticular wax production is not completely understood. In this study, we identified a glossy green mutant (98-1030gl) from the glaucous cabbage inbred line 98-1030. Scanning electron microscopy indicated that the amount of leaf cuticular wax significantly decreased in 98-1030gl. Genetic analysis showed that the glossy green trait was controlled by a single recessive gene. Bulked segregant analysis coupled with whole genome sequencing revealed that the candidate gene for the glossy green trait was located at 13,860,000-25,070,000 bp (11.21 Mb) on Chromosome 5. Based on the resequencing data of two parents and the F2 population, insertion-deletion markers were developed and used to reduce the candidate mapping region. The candidate gene (Bol026949) was then mapped in a 50.97 kb interval. Bol026949 belongs to the Agenet/Tudor domain protein family, whose members are predicted to be involved in chromatin remodeling and RNA transcription. Sequence analysis showed that a single nucleotide polymorphism mutation (C -> G) in the second exon of Bol026949 could result in the premature termination of its protein translation in 98-1030gl. Phylogenetic analysis showed that Bol026949 is relatively conserved in cruciferous plants. Transcriptome profiling indicated that Bol026949 might participate in cuticular wax production by regulating the transcript levels of genes involved in the post-translational cellular process and phytohormone signaling. Our findings provide an important clue for dissecting the regulatory mechanisms of cuticular wax production in cruciferous crops.

Automated summary

This study identified a mutant in a cabbage plant that has reduced cuticular wax production. Based on genetic and genomic analysis, a candidate gene Bol026949 was identified, which belongs to the Agenet/Tudor domain protein family and may play a role in chromatin remodeling and RNA transcription. The mutation in Bol026949 was found to affect its protein translation, which could lead to the decreased production of cuticular wax. Transcriptome profiling suggested that Bol026949 may regulate cuticular wax production by influencing the transcript levels of genes involved in post-translational cellular processes and phytohormone signaling.