Genetic Analysis And Fine Mapping Of The Purple Gene In Purple Heading Chinese Cabbage

Chinese cabbage(Brassica campestris L.ssp.pekinensis Olsson),spreading widely all over the world,is one of the largest vegatable crop in our country,and occupied an important role in human nutritious diet.It was known that the natural anthocyanin in plant not only possess significant role in plants self-development,but also has potential medical and healthcare functions in preventing our body from cancer,atherosclerosis and other cardiovascular diseases due to its preferable antioxidant ability.The accumunation of anthocyanin in cell vacuole is one of the crucial reson for purple trait development of purple heading Chinese cabbage.Therefore,investigating the genetic mechanism of purple trait and fine mapping the purple candidate gene by traditional molecular makers have important significance on breeding purple heading Chinese cabbage with rich anthocyanin.This study was based on our special purple heading Chinese cabbage possessing independent intellectual property rights,14S839 as male parent and orange heading Chinese cabbage 14S162 as female parent.A F2 population was constructed by them to finely map the purple gene(BrPur)controlling purple inner leaves trait of Chinese cabbage.Firstly,the genetic pattern of purple phenotype was investigated by analysing the separation ratio of purple trait among F2 population.Secondly,the purple candidate gene was primarily mapped by phenotype linkage analysis and molecular marker analysis with modified BSA method.Finally,fine mapping of the purple candidate gene was conducted using tight linkaeg markers designed and developed by the annotation information in BRAD.The significative discoveries in this paper are as follows:Firstly,the purple heading phenotype in the purple Chinese cabbage was controlled by one incomplete dominant gene according to the segregation ratio of heads color in 2014 and2015 field investigation(χ(3:1,2014)=0.101 <χ(0.05,1)=3.84,χ(3:1,2015)=2.613<χ(0.05,1)=3.84),as well as the diversity of purple degree among the purple individuals of F2.Secondly,the BrPur was primarily mapped in the interval CL-12 and B214-87 on linkage group A07 by the modified BSA method,the physical distance is 577.235 Kb.Finally,we firstly constructed the high density genetic map of the BrPur controlling anthocyanin accumulation in purple heading Chinese cabbage on A07 linkage group,and mapped the BrPur in a 47.91 Kb region and developed two tightly linkage flanking markers QJ-46 and SSR14-36,with the inheritant distance 0.1 c M and 0.6 cM respectively.