Inheritance And Fine Mapping Of The Glossy Gene In Cabbage

Cabbage(Brassica oleracea L. var. capitata L.)is an important Cruciferous Brassica vegetable. The planting area of Cabbage has achieved 900, 000 hm2 in China each year.The leaf color of normal cabbage is green, grey green or dark green. Generally, there is a wax layer covering the leaf surface of normal cabbage. Glossy materal is the mutant of normal cabbage, it shows glossy in leaf surface, green color, good commodity nature, and rich nutrition. It has a remarkable difference comparing with normal cabbage and it has very important significance for riching Cabbage Germplasm resources. At present, the systematic study of the formation of cabbage Glossy traits and their influence on plant growth and development, as well the practical application potential is lacking. There are extensive studies on the inheritance of Glossy traits in Brassica oleracea, but the inheritance of Glossy traits exists diversity in different materials. Nonetheless, there has rarely reported about the mapping of Glossy gene in Cabbage. Through characteristics study of cabbage Glossy mutant, we have made clear the formation of cabbage Glossy traits and their influence on plant growth and development, as well the practical application potential. Through genetic analysis, we have made clear the inheritance of the Glossy mutant. The Glossy gene BOGL-2 was fine mapped in the first time. The main results were as follows:1. Studies on Characteristics of Glossy mutant cgl-2 in cabbageThe amount of epicuticular wax over the mutant plant was just about 30% compared to the wild type. Also the wax crystal structure of the mutant plant was different from the wild type. In the wild type, the wax composition was mainly consisted of alkanes, alcohols, fatty acids, ketones, and aldehydes, while in the mutant there were severely lack of alkanes and ketones. We speculated that the biosynthetic pathway of alkane in the mutant was blocked, so it exhibited Glossy on leaves. In addition, cuticle permeability was obviously increased in the Glossy mutant. The results of growth curve indicated that the growth speed of cgl-2 was not affected. The study on agronomic traits of the mutant showed that the color of Glossy mutant was bright green and the Glossy mutant exhibited better commodity nature. Besides, the bright green F1 cabbage had the advantage of heterosis indicating that the Glossy mutant possessed potential value for practical application.2. Genetic analysis of Glossy mutant cgl-2F1 plants of cgl-2×M36 were all exhibit Glossy traits as cgl-2.In F2 pupulation,the ratio of Glossy plants to waxy plants was 2.91:1. The ratio of Glossy plants to waxy plants was 0.96:1 in BC1P2 population. That were all Glossy plants in another backcross population. Genetic analysis showed that the Glossy traits on cabbage cgl-2 was controlled by one single dominant gene.3. Fine mapping of Glossy gene BOGL-2In order to find the polymorphic DNA primers between cgl-2 and M36, The DNA of parents and there F1 were used as template to screen the g SSR primers. As a result, we obtained 66 co-dominant markers. 13 F2 plants were used to validate the 66 primers, we found that marker g SSR748 was linked with the Glossy gene BOGL-2. Then 93 F2 plants were used to calculate the genetic distance between g SSR748 and BOGL-2, the results showd that the genetic distance of that was 3.2c M. We designed another 108 SSR primers in the mapping location, and enlarged the F2 population to 1088 individuals.Finally, we located the Glossy gene BOGL-2 between marker C08-g SSR98 and the chromosome ends, the genetic distance of BOGL-2 and marker C08-g SSR98 was 0.18 c M, the physical distance between C08-g SSR98 and the ends of chromosome was 33.5kb.In addition, BC1P2 population of cgl-2×M36 and F2 population of cgl-2×201 were also used as mapping population, the mapping results were similar as the mapping result of F2 population of cgl-2×M36.