Laboratório de Bioquímica Genética de Plantas, 212, BIOAGRO, Universidade Federal de Viçosa, Viçosa, MG, 36570-000, Brazil.
Seeds Bayer Crop Science, Rodovia GO 174, KM 11, Rio Verde, GO, Brazil.
Theor Appl Genet. 2018 May;131(5):1099-1110. doi: 10.1007/s00122-018-3061-2. Epub 2018 Feb 3.
We molecularly characterized a new mutation in the GmFAD3A gene associated with low linolenic content in the Brazilian soybean cultivar CS303TNKCA and developed a molecular marker to select this mutation. Soybean is one of the most important crops cultivated worldwide. Soybean oil has 13% palmitic acid, 4% stearic acid, 20% oleic acid, 55% linoleic acid and 8% linolenic acid. Breeding programs are developing varieties with high oleic and low polyunsaturated fatty acids (linoleic and linolenic) to improve the oil oxidative stability and make the varieties more attractive for the soy industry. The main goal of this study was to characterize the low linoleic acid trait in CS303TNKCA cultivar. We sequenced CS303TNKCA GmFAD3A, GmFAD3B and GmFAD3C genes and identified an adenine point deletion in the GmFAD3A exon 5 (delA). This alteration creates a premature stop codon, leading to a truncated protein with just 207 residues that result in a non-functional enzyme. Analysis of enzymatic activity by heterologous expression in yeast support delA as the cause of low linolenic acid content in CS303TNKCA. Thus, we developed a TaqMan genotyping assay to associate delA with low linolenic acid content in segregating populations. Lines homozygous for delA had a linolenic acid content of 3.3 to 4.4%, and the variation at this locus accounted for 50.83 to 73.70% of the phenotypic variation. This molecular marker is a new tool to introgress the low linolenic acid trait into elite soybean cultivars and can be used to combine with high oleic trait markers to produce soybean with enhanced economic value. The advantage of using CS303TNKCA compared to other lines available in the literature is that this cultivar has good agronomic characteristics and is adapted to Brazilian conditions.
我们对巴西大豆品种 CS303TNKCA 中与亚麻酸含量低相关的 GmFAD3A 基因的新突变进行了分子特征分析，并开发了一种分子标记来选择该突变。大豆是全球最重要的农作物之一。大豆油含有 13%的棕榈酸、4%的硬脂酸、20%的油酸、55%的亚油酸和 8%的亚麻酸。育种计划正在开发高油酸和低多不饱和脂肪酸（亚油酸和亚麻酸）的品种，以提高油的氧化稳定性，使品种更受大豆产业的欢迎。本研究的主要目的是表征 CS303TNKCA 品种的低亚麻酸特性。我们对 CS303TNKCA 的 GmFAD3A、GmFAD3B 和 GmFAD3C 基因进行了测序，并在 GmFAD3A 外显子 5 中发现了一个腺嘌呤点缺失（delA）。这种改变产生了一个过早的终止密码子，导致只有 207 个残基的截断蛋白，从而产生无功能的酶。通过在酵母中异源表达分析酶活性，支持 delA 是 CS303TNKCA 中低亚麻酸含量的原因。因此，我们开发了一种 TaqMan 基因分型检测方法，将 delA 与分离群体中的低亚麻酸含量相关联。纯合 delA 的系亚麻酸含量为 3.3%至 4.4%，该基因座的变异解释了表型变异的 50.83%至 73.70%。这个分子标记是一个将低亚麻酸特性导入优良大豆品种的新工具，并且可以与高油酸特性标记结合使用，以生产具有更高经济价值的大豆。与文献中其他可用的品系相比，CS303TNKCA 的优势在于，该品种具有良好的农艺特性，适应巴西的条件。
