以白色的野生胡萝卜‘松滋野生’(Ws)和橘色的栽培胡萝卜品种‘Amsterdam’(Af)为亲本构建的回交重组自交系(BIL)为试材,基于低倍重测序技术开发SNP标记,构建了由1 976个Bin标记组成,包含29 435个SNP标记的遗传图谱。图谱总距离834.28 c M,平均图距0.42 c M。通过对胡萝卜肉质根中类胡萝卜素含量相关QTL分析,在连锁群LG04和LG08中检测到调控α–胡萝卜素、β–胡萝卜素、ζ–胡萝卜素、叶黄素、玉米黄质和总类胡萝卜素含量的主效QTL(M-QTL)2、2、3、2、2和2个,表型贡献率为11.47%~19.18%;另检测到调控α–胡萝卜素、β–胡萝卜素、ζ–胡萝卜素、玉米黄质和总类胡萝卜素含量的上位性QTL(E-QTL)1、1、2、1和1个,表型贡献率为2.50%~3.66%。在M-QTL显著区间内共检索到36个有功能注释的预测基因,其中Dck018297为ζ–胡萝卜素脱氢酶2基因,与调控β–胡萝卜素合成和总类胡萝卜素含量有关;Dck008006为乙烯响应因子2.2的同源基因,与调控α–胡萝卜素、ζ–胡萝卜素合成有关;Dck029898为转录因子b HLH135的同源基因,与调控玉米黄质合成有关。
Based on whole-genome resequencing data,a high resolution genetic map was developed by using a set of backcross inbred lines(BILs)crossed by a wild species‘Songzi’with a cultivar‘Amsterdam’,and used to map QTLs for main carotenoids in carrot root. Finally,the genetic map was consisted of 1 976 Bins which contained 29 435 SNPs. The total genetic distance of map was 834.28 c M with an average interval of 0.42 c M between Bin markers. There were 2,2,3,2,2 and 2 main-effect QTLs(M-QTLs)associated with α-carotene,β-carotene,ζ-carotene,lutein,zeaxanthin and total carotenoid contents,respectively,with 11.47%–19.18% phenotypic variance. There were 1,1,2,1 and 1 epistatic QTLs contributed to α-carotene,β-carotene,ζ-carotene,zeaxanthin and total carotenoid contents,respectively,with 2.50%–3.66% phenotypic variance. A total of 36 predicted genes with function annotations were detected in M-QTLs. Among these,gene Dck018297 was ζ-carotene desaturase and associated with β-carotene biosynthesis and total carotenoid contents;gene Dck008006 homologouse to ERF2.2 was associated with α-carotene and zeaxanthin biosynthesis;gene Dck029898 homologouse to b HLH135 was associated with ζ-carotene biosynthesis. These three candidate genes might play central roles in the carotenoid biosynthesis in carrot root.