Brassica napus is an important oilseed crop in the world, and the mechanism of seed oil biosynthesis in B. napus remains unclear. In order to study the mechanism of oil biosynthesis and generate germplasms for breeding, an ethyl methanesulfonate (EMS) mutant population with ~100 000 M2 lines was generated using Zhongshuang 11 as the parent line. The EMS‐induced genome‐wide mutations in M2−M4 plants were assessed. The average number of mutations including single nucleotide polymorphisms and insertion/deletion in M2−M4 was 21 177, 28 675 and 17 915, respectively. The effects of the mutations on gene function were predicted in M2−M4 mutants, respectively. We screened the seeds from 98 113 M2 lines, and 9415 seed oil content and fatty acid mutants were identified. We further confirmed 686 mutants with altered seed oil content and fatty acid in advanced generation (M4 seeds). Five representative M4 mutants with increased oleic acid were re‐sequenced, and the potential causal variations in FAD2 and ROD1 genes were identified. This study generated and screened a large scale of B. napus EMS mutant population, and the identified mutants could provide useful genetic resources for the study of oil biosynthesis and genetic improvement of seed oil content and fatty acid composition of B. napus in the future.

中文翻译：

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甘蓝型油菜种子油含量或脂肪酸组成改变的EMS突变体的开发和筛选

甘蓝型油菜是世界上重要的油料作物，其油菜的生物合成机理还不清楚。为了研究油的生物合成机理并产生育种种质，以中双11为亲本，产生了约10万M2品系的甲磺酸乙酯（EMS）突变体。评估了EMS诱导的M2-M4植物全基因组突变。M2-M4中包括单核苷酸多态性和插入/缺失在内的平均突变数分别为21 177、28 675和17 915。分别在M2-M4突变体中预测了突变对基因功能的影响。我们从98 113 M2系中筛选了种子，并鉴定出9415个种子油含量和脂肪酸突变体。我们进一步证实了686个突变体的种子油含量和脂肪酸在先进世代中发生了改变（M4种子）。重新测序了五个具有增加的油酸的代表性M4突变体，鉴定了FAD2和ROD1基因。该研究产生并筛选了大规模的油菜芽孢杆菌EMS突变体种群，这些鉴定出的突变体可为油生物合成以及油菜种子油含量和脂肪酸组成的遗传改良研究提供有用的遗传资源。