青海大黄油菜Brsc1基因的精细定位及图谱整合

大黄油菜是源于青海湟源的地方品种,种皮颜色鲜黄,其大黄油菜的黄籽性状受1对隐性基因(Brsc1)控制,该基因被定位于白菜A9染色体上一段1.7 Mb的区间内。为了更好地利用这一黄籽资源,对Brsc1基因进一步精细定位。利用青海大黄油菜和褐籽白菜型油菜09A-126构建BC4及F2分离群体。利用白菜同源区段内已公布的SSR标记,同时利用该区段序列信息开发新的SSR引物,共获得6个与目标基因紧密连锁的标记(Br ID10711、Br A5~Br A9),其中Br A5与目标基因共分离,Br A9为一侧最近标记,它与目标基因之间的遗传图距为0.69 c M。至此,Brsc1基因进一步被限定于标记Y06和Br A9之间约1.2 Mb的区间内。利用本研究中获得的标记检测F2群体中3种类型单株,鉴定出一个共显性标记Br A8。将本研究中获得的SSR标记与前人研究结果进行整合,加密了Brsc1基因所在区间的标记密度。同时,特异片段与拟南芥基因组进行序列比对的结果表明,共有5个标记与拟南芥的第1染色体有较好的共线性关系,暗示Brsc1基因的同源基因可能位于拟南芥的第1染色体上。本研究中获得的标记将为Brsc1基因的克隆及利用Brsc1基因进行黄籽油菜的分子辅助育种提供有利条件。

Fine Mapping and Map Integration of Brsc1 Gene in Dahuang Rape (Brassica rapa L.)

Dahuang rape, a landrace originated from Qinghai Huangyuan, has bright yellow seed coat. Previous studies indicated that the yellow-seeded trait in Dahuang was controlled by a recessive gene (Brsc1), which was located in a 1.7 Mb interval on chromosome A9 of Brassica rapa (B. rapa). In order to better use the yellow-seeded resource, we further fine mapped the Brsc1 gene. BC₄ and F₂ populations, constructed from the cross of Dahuang and 09A-126 (brown-seeded, B. rapa), were used for fine mapping. New PCR markers were developed based on the information of the homologous region in B. rapa and the published SSR markers were used in polymorphism survey. A total of six markers (BrID10711, BrA5-BrA9) tightly linked to the target gene were obtained, wherein BrA5 co-segregated with Brsc1, and BrA9 was 0.69 cM away from the Brsc1 gene. So Brsc1 was further limited in a 1.2 Mb interval, approximately. The markers identified in this study were used to detect three types of individual plants in F₂ population. BrA8 was identified as a co-dominant marker. Marker density of the region encompassing the Brsc1 gene was increased by integrating the markers from previous researches and this study. Sequence alignment with the genome of Arabidopsis thaliana was performed and a good homologous linear relationship between five markers and chromosome 1 of Arabidopsis thaliana was detected, which implied that homologous gene of the Brsc1 gene maybe located in the chromosome 1 of Arabidopsis thaliana. Markers obtained from this study would provide favorable conditions for map-based cloning of the Brsc1 and molecular marker-assisted selection (MAS) breeding of the yellow-seeded rape.