不同胡麻品种TAG合成途径关键基因表达与含油量、脂肪酸组分的相关性分析

摘要

胡麻是一种富含不饱和脂肪酸尤其是α-亚麻酸的油料作物, 明晰TAG合成途径中与胡麻含油量和脂肪酸组分相关的基因具有重要的理论意义.以3个含油量和脂肪酸组分有显著差异的胡麻品种 (系) 为材料, 分析了不同品种 (系) 、不同组织和不同发育阶段胡麻油脂和脂肪酸组分的动态积累模式和TAG合成途径中7个关键基因的动态表达模式, 以及含油量和不饱和脂肪酸与7个关键基因表达的相关性.结果表明, 胡麻开花后10～20d, 是种子油脂和亚麻酸的快速积累期, 且不同胡麻品种 (系) 油脂和亚麻酸的动态积累模式差异显著.TAG合成途径中的7个关键基因 (GPAT9、DGAT1、DGAT2、PDAT1、PDAT2、FAD2A和FAD3A) 在胡麻不同发育阶段的不同组织中均有表达, 在不同品种 (系) 间的表达模式各不相同.其中PDAT1、DGAT1和DGAT2基因的动态表达模式与含油量的动态积累模式显著正相关, PDAT1的动态表达模式与亚麻酸的动态积累模式显著正相关, 且在高油高亚麻酸材料的种子动态发育阶段中PDAT1基因的累积表达量也显著高于低油低亚麻酸材料.因此, PDAT1可能是影响胡麻不同品种 (系) 中含油量和亚麻酸含量的关键基因.%Flax (Linum usitatissimum) is an oil crop containing abundant unsaturated fatty acids, especiallyα-linolenic acid.To better underst and biosynthesis of these compounds, it is highly relevant to explore functions of genes in the TAG (triacylglycerol) synthesis pathway, which are associated with flax oil content and levels of various fatty acid components.In this study, the dynamic accumulation patterns of oil and fatty acid components in flax and the corresponding expression patterns of 7 key genes in the TAG synthesis pathway were determined in three varieties (lines) of flax identified as having significant differences in oil content or fatty acid composition.The correlations between expression patterns of 7 key genes, oil contents and unsaturated fatty acid levels were analyzed.It was found that seed oil and linolenic acid accumulate rapidly between 10 and 20 days after flowering in flax.However, the time course of the accumulation patterns of oil and linolenic acid differed significantly in the three varieties studied.Meanwhile, in the TAG synthesis pathway the 7 key genes (GPAT9, DGAT1, DGAT2, PDAT1, PDAT2, FAD2A, and FAD3A) were found to be expressed in different flax tissues at different stages of development, with the patterns of expression also differing among the three lines.The expression patterns of PDAT1, DGAT1, and DGAT2were positively correlated with the dynamic accumulation pattern of oil content, and the pattern of PDAT1was significantly positively correlated with the accumulation pattern of linolenic acid.In addition, the cumulative expression of PDAT1in high oil and high-linolenic-acid flax germplasm is also significantly higher than that in low-oil and low-linolenic-acid material during seed development.Therefore, PDAT1appears to be a key gene in the regulation of oil and linolenic acid content in different varieties (lines) of flax.