Genetic and physical fine mapping of a multilocular gene Bjln1 in Brassica juncea to a 208-kb region
Genetic and physical fine mapping of a multilocular gene Bjln1 in Brassica juncea to a 208-kb region
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芥菜中多室基因 Bjln1 到 208 kb 区域的遗传和物理精细定位
DOI：
10.1007/s11032-013-9877-1
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发表时间：
2013-08-01
影响因子：
3.1
通讯作者：
Zhao, Hongchao
中科院分区：
文献类型：
--
作者：
Xiao, Lu;Zhao, Huiyan;Zhao, Hongchao
芥菜大部分种质资源产生只有2个房室的硅橡胶，少数品种可以产生3个或4个房室的硅橡胶。研究表明，芥菜子房室数的增加会导致单株种子数量的增加，从而导致单株产量的增加。因此，培育高室数品种可能是提高芥菜产量的有效途径。遗传分析表明，多石的高室数性状是由两个隐性基因决定的，暂定为Bjln1和Bjln2。为了精确定位Bjln1基因，我们将多房亲本（Duoshi）与双眼亲本新洁（Xinjie）杂交形成BC3群体。利用扩增片段长度多态性（AFLP）和散装分离分析相结合，仅鉴定出两个与Bjln1相关的AFLP标记。初步连锁分析表明，这两个AFLP标记位于Bjln1的同侧。Blast分析表明，这两个AFLP标记序列在B. rapa A7底部的Scaffold000019上具有同源物。利用连锁分析和BlastN检索结果，利用rapa A7的序列信息开发了SSR （simple sequence repeat）标记。最终鉴定出7个SSR标记，其中ln8与Bjln1共分离。ln7和ln9是距离Bjln1基因最近的标记，分别位于2.0和0.4 cM处。将SSR标记克隆、测序并定位于rapa的A7（对应于juncea A基因组的J7）上。在rapa A7的一个208kb的基因组区域内定位了两个最接近的标记ln7和ln9，其中可能包含Bjln1基因。本研究可为芥菜Bjln1基因的克隆及标记辅助选择和基因工程选育多房品种提供技术支持。
Most of the germplasm resources in Brassica juncea produce silique with only two locules, whereas a few varieties can produce silique with three or four locules. The increase in locule number in B. juncea has been shown to cause an increase in the number of seeds per silique, resulting in an increase in the yield per plant. Thus, the development of high-locule-number varieties may be an effective way of improving the yield of B. juncea. Duoshi, a B. juncea landrace originating from the Qinghai-Tibetan plateau, produces silique with 3-4 locules. Genetic analysis has shown that the high-locule-number trait in Duoshi is determined by two recessive genes, tentatively designated as Bjln1 and Bjln2. For fine mapping of the Bjln1 gene, a BC3 population was developed from the cross between Duoshi (multilocular parent) and Xinjie (bilocular parent). Using a combination of amplified fragment length polymorphism (AFLP) and bulked segregant analysis, only two AFLP markers linked to Bjln1 were identified. Preliminary linkage analysis showed that the two AFLP markers were located on the same side of Bjln1. Blast analysis revealed that the sequences of the two AFLP markers had homologues on Scaffold000019 at the bottom of B. rapa A7. Using the results of linkage analysis and BlastN searches, simple sequence repeat (SSR) markers were subsequently developed based on the sequence information from B. rapa A7. Seven SSR markers were eventually identified, of which ln 8 was co-segregated with Bjln1. ln 7 and ln 9, the closest flanking markers, were mapped at 2.0 and 0.4 cM distant from the Bjln1 gene, respectively. The SSR markers were cloned, sequenced and mapped on A7 of B. rapa (corresponding to J7 in the A genome of B. juncea). The two closest flanking markers, ln 7 and ln 9, were mapped within a 208-kb genomic region on B. rapa A7, in which the Bjln1 gene might be included. The present study may facilitate cloning of the Bjln1 gene as well as the selection process for developing multilocular varieties in B. juncea by marker-assisted selection and genetic engineering.