油菜N13和N18上含油量QTL作图区间相关候选基因克隆

Cloning of candidate genes in oil content QTL region of N13 and N18 in Brassica napus L

以前人报道的SG-图谱和DH群体为材料,利用拟南芥脂质基因库和芸薹属EST库信息资源,选择与拟南芥中诠释的重要油脂合成相关基因高度同源的甘蓝型油菜EST和其他具有基因信息的EST序列为标记来源,发展功能基因标记加密SG图谱;对定位在N13和N18连锁群上含油量QTL区间的相关基因片段进行克隆、测序和生物信息学分析,以期获得可能与种子含油量QTL有关联的侯选基因。结果表明:在2条连锁群的3个含油量QTL区域内共连锁上6个功能基因,其中与拟南芥同源的3个基因在油脂合成途径中发挥重要作用;其双亲差异片段经克隆测序和比对分析,发现有2个在双亲间存在氨基酸水平差异;将获得的基因片段和拟南芥同源基因序列比对结果显示,二者间内含子部分核苷酸序列相似率平均为57.7%,外显子区域为86.7%,氨基酸水平上则达到89.2%。

Using Arabidopsis lipid synthesis candidate gene information and their homologous Brassica EST sequences, a set of functional gene markers were developed and integrated into the previously published SG-map. The gene fragments, assigned in the oil content QTL confidence interval on linkage group 13 and 18 （N13 and N18）, were cloned, sequenced and analyzed to identify the oil content-related candidate genes. The results show that six functional gene fragments were mapped on the target QTL regions. Of them, three involved in the lipid synthesis pathways, which were homologous genes of functional importance in Arabidopsis. Blasting the sequences of these gene fragments between two parents ＂Sollux＂ and ＂Gaoyou＂, some differences were identified in amino acid level. Further comparison among cloned fragments, published Brassica ESTs and corresponding sequences of Arabidopsis genes revealed that the favorable alleles were associated with mutant parent, and in total, an average of 57.7%, 86.7% and 89.2% similarities were observed in the part of intron, exon and amino acid level, respectively, between Brassica napus gene fragments and homologous Arabidopsis gene sequences.