甘蓝型油菜胚色素成分的QTL定位

QTL Mapping of Embryonic Pigment Components in Brassica napus

以甘蓝型黄籽油菜GH06和甘蓝型黑籽油菜中油821为亲本杂交,后代通过"一粒传法"连续自交7代构建重组自交系,2007年分别在重庆市北碚区和万州区两个试验基地种植重组自交系群体,利用本实验室已构建的遗传连锁图谱和复合区间作图法(CIM),分析种胚色素的4种主要成分的QTL。结果共检测到31个QTL,分别位于14个不同的连锁群,其中5个花色素含量有QTL,分别位于第1、5、10、16和20连锁群,单个QTL解释表型变异的6.08%～11.67%;10个类黄酮含量有QTL,分别位于第1、3、6、7、12、20和25连锁群,单个QTL解释表型变异的4.48%～11.10%;8个总酚含量有QTL,分别位于第1、2、12、16和20连锁群,单个QTL解释表型变异的5.24%～10.37%;8个黑色素含量检测到QTL,分别位于第5、8、10、12、14和22连锁群,单个QTL解释表型变异的5.44%～11.32%。解释表型变异大于10%的5个QTL,包括2个类黄酮含量QTL,花色素含量、总酚含量和黑色素含量QTL各1个,它们分别解释11.10%、10.20%、11.67%、10.37%和11.32%的表型变异。研究结果表明胚色素表现为多基因控制的数量性状,基因表达受环境影响较大,胚与种皮色素的QTL吻合度不高,推测种皮和胚色素合成可能受不同遗传体系控制,与这些QTL紧密相关的分子标记可以用于胚主要色素的分子标记辅助选择。

The quality of rapeseed oil is greatly affected by embryonic pigments. However it has been little research report on the QTL of embryonic pigment components. The objective of this study was to identify QTL controlling embryonic pigment components in Brassica napus using the composite interval mapping （CIM） method. The recombinant inbred lines （RIL） population selfed for 7 successive generations by single seed propagating was derived from a cross between black-seeded male parent cultivar Zhongyou 821 and yellow-seeded female parent line GH06. The population was grown at Beibei and Wanzhou in Chongqing in 2007. Four kinds of embryonic pigment components were identified by constructed genetic map. A total of 31 QTL were detected on 14 different linkage groups. Five QTL for anthocyanidin content were located on linkage groups 1, 5, 10, 16, and 20, respectively, explaining 6.08-11.67% of phenotypic variation; ten QTL for flavonoid content were located on linkage groups 1, 3, 6, 7, 12, 20, and 25, respectively, explaining 4.48-11.10% of phenotypic variation; eight QTL for total phenol content were located on linkage groups 1, 2, 12, 16, and 20, respectively, accounting for 5.24-10.37% of phenotypic variation; and eight QTL for melanin content were located on linkage groups 5, 8, 10, 12, 14, and 22, respectively, explaining 5.44-11.32% of phenotypic variation. Five major QTL explaining over 10% of phenotypic variation were found, including 2, 1, 1, and 1 for flavonoid, anthocyanidin, total phenol and melanin content （qFCB-3-2, qFCW-I-1, qACW-10-1, qTPCW-12-1, and qMCB-22-5）, which accounted for 11.10%, 10.20%, 11.67%, 10.37%, and 11.32% of phenotypic variation respectively. These results suggest that the embryonic pigments are controlled by several minor-effect genes, with a pattern of quantitative trait inheritance, and the expression of the QTL is affected by environmental factors. QTL for seed coat pigments showed little overlapping with those for embryonic pigments, implying that seed coat pigments and embryonic pigments might be controlled by different genetic systems. Molecular markers closely linked with these QTLs could be applied in marker-assisted selection of embryonic pigment components in Brassica napus.