Cgl2 plays an essential role in cuticular wax biosynthesis in cabbage (Brassica oleracea L. var. capitata)

The aerial parts of most land plants are covered with cuticular wax which is important for plants to avoid harmful factors. There is still no cloning study about wax synthesis gene of the alcohol-forming pathway in Brassica species.

Scanning electron microscopy (SEM) showed that, compared with wild type (WT), wax crystal are severely reduced in both the adaxial and abaxial sides of cabbage (Brassica oleracea L. var. capitata L.) leaves from the LD10GL mutant. Genetic analysis results revealed that the glossy trait of LD10GL is controlled by a single recessive gene, and fine mapping results revealed that the target gene Cgl2 (Cabbage glossy 2) is located within a physical region of 170 kb on chromosome 1. Based on sequence analysis of the genes in the mapped region, the gene designated Bol013612 was speculated to be the candidate gene. Gene Bol013612 is homologous to Arabidopsis CER4, which encodes fatty acyl-coenzyme A reductase. Sequencing identified a single nucleotide substitution at an intron/exon boundary that results in an insertion of six nucleotides in the cDNA of Bol013612 in LD10GL. The phenotypic defect of LD10GL was confirmed by a functional complementation test with Arabidopsis mutant cer4.

Our results indicated that wax crystals of cabbage mutant LD10GL are severely reduced and mutation of gene Bol013612 causes a glossy phenotype in the LD10GL mutant.