Authors: Junxiang Zhang Huixia Li Mingke Zhang Maixia Hui Qi Wang Li Li Lugang Zhang
Publish Date: 2013/06/26
Volume: 32, Issue: 4, Pages: 799-805
Abstract
Orange head Chinese cabbage accumulates significant amounts of carotenoids with enhanced nutritional quality To develop molecular markers for breeding of Chinese cabbage lines with high carotenoid content and to isolate the candidate gene underlying carotenoid synthesis we performed fine mapping of the orange locus in a F2S4 mapping population Genetic analysis revealed that the phenotype of the orange head trait was controlled by a single recessive gene Bror The F2S4 mapping population consisting of 1724 individuals was developed from the cross between parental lines 11J16 and 11S392 by continuous selfing of a single heterozygous individual Twentyone tightly linked simple sequence repeat SSR and insertion/deletion polymorphism InDel markers were obtained Highresolution genetic mapping of these markers in the F2S4 mapping population placed BrInDel2 and BrInDel1 at genetic distances of 01 and 02 cM respectively on either side of the Bror locus Based on comparison of these two marker sequences with the fully sequenced Brassica rapa genome the Bror locus was delimited to a 167 kb genomic region Three open reading frames ORFs were predicted in the target region ORF1 encoded carotenoid isomerase which is involved in the isomerization of carotenoids ORF1 was found to be cosegregated with the Bror locus and was thus the most likely candidate gene for Bror The information obtained here will facilitate the breeding of nutrientenriched Chinese cabbage through markerassisted selection and provide a platform for gaining a better understanding of the regulation of carotenoid biosynthesis in these plantsWe thank Dr Xiaowu Wang Institute of Vegetables and Flowers Chinese Academy of Agricultural Sciences for kindly providing the Scaffold sequence in A09 of B rapa and Divyashree C Nageswaran Department of Plant Breeding and Genetics Cornell University for critical reading of the manuscript J X Zhang thanks the support of China Scholarship Council CSC This research was financially supported by the National Natural Science Foundation of China No 31171965 Science and technology support program of China 2012BAD02B01 and 863 plan 2012AA100105
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