甘蓝型油菜遗传图谱的构建及芥酸含量的QTL分析(英文)

Construction of a Molecular Marker Linkage Map and Its Use for QTL Analysis of Erucic Acid Content in Brassica napus L.

一个由甘蓝型油菜品种Quantum(黄花、低芥酸)和人工合成的甘蓝型油菜品系No 2 12 7 17(白花、高芥酸)为亲本材料建立的DH群体中芥酸呈现单基因的遗传模式。为了发展与芥酸紧密连锁的分子标记对其实行有效的控制,随机选择12 1个结实正常的DH系为作图群体,利用SSR和RAPD标记构建了一张甘蓝型油菜的遗传连锁图谱。在亲本间检测到2 0 7个有多态性的遗传标记,其中SSR标记10 3个,RAPD标记有10 2个及2个形态标记(花色和芥酸)。这些标记中有188个标记分配到19个主连锁群和1个小的连锁群A。这些连锁的标记跨越了1183. 3cM ,两标记间的平均间距为6. 3cM ,偏分离比例达到2 0 . 8% (P <0. 0 1)且主要集中在6个连锁群。芥酸主基因定位在LG13上,一个共显性的SSR标记TPS0 .39和一个显性的RAPD标记BS16 4a在它的两侧,遗传距离分别为2 . 2cM和17. 1cM。用区间作图对芥酸进行QTL扫描,仅扫描到该主基因(主效QTL) ,这个QTL解释了约82 %的芥酸表型变异。利用共同的SSR标记与一张BrassicaDB (http :/ /www ukcrop net,作图群体的亲本为N 0 9andSYN1)的连锁图进行比较,结果表明在LG13上可能发生过染色体重排。

Erucic acid is not easily absorbed and therefore is nutritionally undesirable as the long carbon-chain fatty acid in the edible oil derived from Brassica napus . Hence, decreasing erucic acid content is one of the important objectives in double-low (low in erucic acid and low in glucosinolates) breeding program. A monogene controlling erucic acid was found in a doubled haploid (DH) population derived from a cross between a Canadian cultivar Quantum (yellow flower and low erucic acid content) and a resynthesized B. napus line No.2127-17 (white flower and high erucic acid content). In order to identify molecular markers tagging the gene controlling erucic acid, a B. napus linkage map was constructed using the 121 DH lines of the above DH population. A total of 207 markers were detected that comprised 102 random amplified polymorphic DNA (RAPD) markers, 103 simple sequence repeat (SSR) markers and one morphological marker, i.e. the flower colour and erucic acid. One hundred eighty-eight markers were assembled into 19 main linkage groups (LG1-LG19) and a minor group (A). No linkage was found between the remaining 19 markers and any of the established linkage groups. The total map length is 1 183.3 cM with an average distance of 6.3 cM between adjacent markers. The marker loci with distorted segregation ( P <0.01) accounted for 20.8% and tended to cluster in six linkage groups. The major gene for erucic acid was mapped on LG13, flanked by a co-dominant SSR marker TPS039 and a dominant RAPD marker BS164a at genetic distances of 2.2 cM and 17.1 cM, respectively. When QTL mapping was performed using the method of interval mapping, only the major gene (major QTL) was detected. The major QTL explained about 82% of the total phenotypic variation. Compared with a B. napus linkage map constructed based on a cross between N-0-9 and SYN1 in Brassica DB (http://www.ukcrop.net) using some common SSR markers, it was revealed that chromosomal rearrangements might have occurred on LG13.