Correlation between oil content or fatty acid composition and expression levels of genes involved in TAG biosynthesis in flax

doi:10.11686/cyxb2018321

Abstract

Abstract: Flax (Linum usitatissimum) is an oil crop containing abundant unsaturated fatty acids, especially α-linolenic acid. To better understand 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 DGAT2 were positively correlated with the dynamic accumulation pattern of oil content, and the pattern of PDAT1 was significantly positively correlated with the accumulation pattern of linolenic acid. In addition, the cumulative expression of PDAT1 in 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, PDAT1 appears to be a key gene in the regulation of oil and linolenic acid content in different varieties (lines) of flax.

Key words: flax, oil content, linolenic acid, gene expression analysis, correlation analysis

LI Wen-juan, QI Yan-ni, WANG Li-min, DANG Zhao, ZHAO Li, ZHAO Wei, XIE Ya-ping, WANG Bin, ZHANG Jian-ping, LI Shu-jie. Correlation between oil content or fatty acid composition and expression levels of genes involved in TAG biosynthesis in flax[J]. Acta Prataculturae Sinica, 2019, 28(1): 138-149.

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