【作者】 林兵；

【导师】 孟金陵；

【作者基本信息】 华中农业大学 ， 发育生物学， 2010， 硕士

【摘要】 我国作为植物油消费大国,每年进口依存度达61%。而油菜作为我国食用植物油的主要来源,提高其产油量将对保障我国食用油供给安全以及提高我国食用油的供给水平具有重大的作用。同时,油菜因其种子内油酸含量高、亚麻酸含量低而受人们的普遍欢迎。然而油菜“低芥酸”化过程中低芥酸基因的来源是农艺性状上较差的饲料品种,在导入“低芥酸”基因的同时也导入了一些与其紧密连锁的不利于种子油份累积的基因。因此,深入了解甘蓝型油菜种子含油量累积的遗传机制以及打破种子低芥酸含量与低含油量间连锁累赘将对我们培育高含油量新品种具有重要的理论指导意义。本研究中所利用的TN DH群体A8连锁群上能够分别在12个、10个环境下检测到种子含油量QTL和种子芥酸含量QTL,且置信区间重叠。为深入解析A8连锁群上种子含油量QTL簇、明确该连锁群上种子芥酸含量与含油量间关系以及避免该连锁群上种子芥酸含量与含油量间连锁累赘,我们利用比较基因组学的方法在该区间内加密了基于白菜BAC的SSR分子标记并建构了以宁油7号为轮回亲本的近等基因系。主要研究结果如下：通过比较基因组学手段获得了49个甘蓝型油菜A8连锁群对应的已测序白菜BAC,利用这些BAC开发并定位了14个分子标记于A8连锁群种子含油量QTL置信区间。利用加密后的A8遗传连锁图重新检测了种子含油量以及芥酸含量QTL。检测结果表明这一种子含油量QTL簇内QTL数目、位置以及效应大小都有所变化。这一种子含油量QTL簇内QTL经整合后成7个同义QTL筛选BC4F4后获得了4个同义种子含油量QTL对应的近等基因系材料,同时对其表型效应进行了初步分析。种植了8L097-8以及8L099-2两个分离群体用于分析A8连锁群上种子芥酸含量与含油量间关系。综上,通过比较基因组学来利用已测序物种序列信息是加密QTL区间分子标记的有效方法。该区间内所加密分子标记不仅有利于近等基因系筛选,也是将来育种过程中用于打破种子芥酸含量与含油量间连锁累赘的有力工具。所构建的近等基因系材料被成功地用来分解A8连锁群上种子含油量QTL簇以及明确该连锁群上种子芥酸含量与含油量的关系。更多还原

【Abstract】 As a super consumer of plant oil, our country’s level of dependency on import comes to 61%. Seed oil increment of Brassica napus, one of the most important sources of plant oil, will not only secure, but also improve its supply. At the same time, rapeseed oil earns popularity with its character of high oleic acid content and low linolenic acid content. However, primarily from forage rapeseed, genes which are negative to seed oil accumulation together with their tightly linked "lower erucic aicd" gene, were transferred into elite cultivars during the process of "lower erucic acid". Therefore, detailed understanding of genetic mechanism of seed oil accumulation of rapeseed and breaking linkage drag between seed oil content and eruci acid content will theoretically serve as guidelines for breeding higher seed oil content cultivars.We detected seed oil content and erucic acid content QTLs in A8 of TN DH mapping population in 12 and 10 environments, respectively. Evenmore, their confidence intervals overlap. In order to separate this QTL cluster, break linkage drag between seed oil content and erucic acid content and quantify their relationship in A8 linkage group, we have densified this region with BAC-based SSR markers through comparative genomics and constructed NILs through consecutive backcrossing by Ningyou7. Results stated as below:14 BAC-based SSR markers, developed from 49 sequenced BAC of Brassica rapa, were mapped in this QTL region through comparative genomics.Result of redetecting seed oil and erucic acid content QTL of A8 linkage group demonstrated that number, location, and effect of QTLs differed significantly from those before. Seed oil cotent QTLs of this region were integrated into 7 consensus QTLs after meta-analysis.NILs corresponding to 4 consensus seed oil content QTLs were selected from BC4F4, and their genotypic effects were analyzed as well. Two segregating populations,8L097-8 and 8L099-2, were planted to analyze the relationship between seed oil content and erucic acid content in linkage group A8.In sum, utilization of sequenced DNA information through comparative genomics is an efficient way to densifying QTL region with molecular markers. These markers will not only be helpful in selecting NILs, but also serve as important tools for breaking linkage drag between seed oil content and erucic acid content in A8 during future rapeseed breeding programs. Selected NILs have been successfully used to separate seed oil content QTL cluster and quantify the relationship between seed oil content and eruci acid content in A8.更多还原