高油酸低脂氧合酶(FAD-LOX)多基因编辑大豆优异种质创制

Generation of Excellent Soybean Germplasm with High Oleic Acid and Low Lipoxygenase by Multigene Editing

大豆是植物油和蛋白质的主要来源。不饱和脂肪酸的含量是影响植物油品质的主要因素,油酸是不饱和脂肪酸中含量最丰富的成分之一,具有较强的氧化稳定性和热稳定性。增加油酸的含量可以提高大豆油的耐储存性,也有利于人体健康。GmFAD2-1A和GmFAD2-1B是大豆编码脂肪酸去饱和酶,调控油酸向亚油酸转化的关键基因。脂氧合酶是大豆种子中的抗营养因子之一。它在酶促氧化的条件下产生豆腥味,限制了大豆产品的应用。为满足不同人群的需要和降低加工成本,有必要培育无脂氧合酶的突变品系。大豆中GmLOX基因(包括GmLOX1、GmLOX2、GmLOX3)编码脂氧合酶。脂氧酶也能催化亚油酸氧化生成脂质氢过氧化物,然后形成豆腥味。因此,降低亚油酸的含量有助于减少豆腥味的形成。同时编码脂氧酶也能延缓豆油的酸败。本研究利用CRISPR/Cas9对中吉602的GmFAD2-1A、GmFAD2-1B、GmLOX1、GmLOX2和GmLOX3基因进行编辑。通过农杆菌介导的大豆遗传转化,在T2代分离到7个具有不同等位变异的优异新种质。与中吉602相比,突变体种子中脂氧合酶活性显著降低,油酸含量提高至81.7%~83.5%。本研究为有效开发大豆种质资源以满足不断变化的市场需求提供了新材料。

Soybean is a major source of plant oil and protein.The content of unsaturated fatty acid is the main factor to affect quanlity of plant oil.Oleic acid is one of the most abundant ingredient in unsaturated fatty acid,it has strong oxidation stability and thermal stability.Increasing the content of oleic acid can enhance the storability of soybean oil,it is also beneficial to human health.GmFAD2-1A and GmFAD2-1B are key genes to encode fatty acid desaturase,regulate the conversion of oleic acid to linoleic acid.Lipoxygenase is one of the antinutritional factors in soybean seeds.It can produce beany flavor under the condition of enzymatic oxidation,which restricts human consumption of soybean.It is desirable to generate lipoxygenase-free new mutant lines to improve the eating quality of soybean oil and protein products.GmLOX genes(including GmLOX1,GmLOX2 and GmLOX3)encode soybean lipoxygenase.It can also catalyze the oxidation of linoleic acid to produce lipid hydroperoxides,and then form a beany flavor.Therefore,reducing the content of linoleic acid is helpful to reduce the formation of bean flavor.In this study,CRISPR/Cas9 was used to edit GmFAD2-1A,GmFAD2-1B,GmLOX1,GmLOX2 and GmLOX3 in Zhongji 602.Seven homozygous five-gene mutants with different alleles were isolated in T2 generation by Agrobacterium-mediated genetic transformation of soybean.Compared with Zhongji 602,the activity of lipoxygenase was significantly decreased,and the content of oleic acid was increased to 81.7%-83.5%in the mutants seeds.These mutants could be used for beany flavor reduction and creation of high oleic acid soybeans to provide a framework to efficiently develop soybean germplasm to meet changing market demands.