Fine-mapping And Analysis Of Cgl-1,a Gene Conferring Glossy Trait In Cabbage(Brassica Oleracea L.var.capitata)

Cabbage belongs to Brassica of Cruciferae,a variety of Brassica oleracea L.It is one of the major cultivated vegetables in China and occupied an important position in annual vegetables supply and exportation trade.Leafy head is the product and edible organs of cabbage and the leafy head color is a very important commodity trait in cabbage breeding.Generally,normal cabbage present green,grey green or dark green due to the wax layer which covers on the surface leaf.Wax-less material originate from the mutation of normal cabbage and shows glossy and brilliant green color on leaf surface.Wax-less cabbage mutant plays an important role in riching cabbage germplasm resources and facilitating brilliant green cabbage breeding.Researches on the inheritance of glossy traits and mapping mutant genes may lay the foundation for the future application of this trait in production practice and the functional verification of the mutant genes.In this study,the characteristics of wax-less mutants were explored by studying the glossy mutants 10Q-961 and g21-3,and the inheritance of glossy traits were clarified.Two genes cgl-1.1 and cgl-1.2 controlling glossy trait in 10Q-961 and g21-3 respectively were mapped and analyzed,and two molecular markers ISP1 and Dcgl-1.2 which completely linked to the glossy phenotype were developed.The main findings are as follows:1.The wax-less mutants 10Q-961 and g21-3 are significantly different from its corresponding wild type respectively during the whole developmental process.Cuticular waxes of the wax-less mutants 10Q-961 and g21-3 were not completely missing and a small amount of wax still existed.The waxy crystal structure in mutants were different from its wild type.Alkanes and ketones were the main missing components in the wax-less mutants.2.The glossy trait of wax-less mutants 10Q-961 and g21-3 was both controlled by a single recessive gene,and the glossy phenotype of this two mutants was controlled by the same locus.3.The glossy gene cgl-1.1 of wax-less mutant 10Q-961 was fine-mapped to a 188.7-kb interval between the C08SSR61 simple sequence rdpeat marker and the end of chromosome C08.According to gene annotation and homology analyses,the Bol018504 gene,which is a homolog of CER1 in Arabidopsis thaliana,was the most likely candidate for the cgl-1.1 gene.An insertion of 2,722 bp base in the first intron of the Bol018504 gene resulted in the activity loss of the aldehyde decarbonylation coded by cgl-1.1 and conferred this mutant a glossy phenotype.4.The glossy gene cgl-1.2 of wax-less mutant g21-3 was cloned based on the fine-mapping result of cgl-1.1,and the sequence result revealed that a G to C base mutation occurred at 827th base in CDS sequence of the Bol018504 gene may be the cause of the glossy phenotype of this mutant.5.Two molecular markers ISP1 and Dcgl-1.2 which were completely linked to the glossy trait in mutants 10Q-961 and g21-3 respectively were developed according to the mutation style of cgl-1.1 and cgl-1.2.These markers can be used for auxiliary selection of bright green cabbage material,with the accuracy of 100%.