不同沙棘品种种子中α-亚麻酸含量差异及相关基因分析

Analysis of α-Linolenic Acid Content and Related Genes in Seeds of Sea Buckthorn Cultivars

[目的]探讨α-亚麻酸含量存在差异的2个沙棘品种种子中的基因调控差异,为进一步提高沙棘种子中α-亚麻酸含量、培育沙棘良种奠定基础。[方法]以2个不同品种的沙棘种子为研究对象,通过气相色谱-质谱分析和转录组测序分析确定2个沙棘品种种子中的α-亚麻酸含量差异以及相关差异表达基因。[结果]蒙古大果沙棘(Hippophae rhamnoides‘Mongolia’向阳)(XY)和中国沙棘(H.rhamnoides‘Sinensis’丰宁)(FN)种子中的α-亚麻酸含量占比不同,XY中含量最高的脂肪酸是α-亚麻酸,其次是亚油酸,而FN中α-亚麻酸含量次于亚油酸。半成熟期(T2),基因FAD2和基因FAD3在XY中的表达量均显著高于FN,分别是FN的3.83倍和13.63倍。未成熟期(T1)和T2时期基因FAD7在XY中的表达量均显著高于在FN中的表达量,分别是FN的2.09倍和1.72倍。相反,T2时期基因LOX3.1和LOX3.2在FN中的表达量均高于XY,分别是XY的8.02倍和7.12倍。[结论]沙棘种子中α-亚麻酸的高积累源于多个基因的协同作用,基因FAD2、FAD3、FAD7的高表达和基因LOX3.1和LOX3.2的低表达共同调控α-亚麻酸的高积累。

[Objective] To study the differences of gene regulation in seeds of two sea buckthorn(Hippophae rhamnoides) cultivars with different α-linolenic acid content and to find the method of further increase the content of α-linolenic acid in H. rhamnoides seed. [Method] The difference in α-linolenic acid content and the expressed genes in the seeds of two H. rhamnoides cultivars were analyzed and determined by gas chromatography-mass spectrometry and transcriptomics. [Result] The proportion of α-linolenic acid in H. rhamnoides ’Mongolia’(XY) and H. rhamnoides ‘Sinensis’(FN) seeds was different. The fatty acid with the highest content of XY was α-linolenic acid, followed by linoleic acid. The content of α-linolenic acid in FN was lower than that of linoleic acid. In semi-mature stage(T2), the expression levels of gene FAD2 and gene FAD3 in XY were 3.83 times and 13.63 times that in FN respectively. The expression of gene FAD7 in XY was 2.09 times and 1.72 times that in FN in immature stage(T1) and T2 respectively. It was consistent with the trend of linoleic acid and α-linolenic acid content. On the contrary, the expressions of gene LOX3.1 and gene LOX3.2 in FN were 8.02 times and 7.12 times that of XY in T2 respectively.[Conclusion] The high accumulation of α-linolenic acid in H. rhamnoides seeds is due to the synergistic effect of multiple genes. High expression of gene FAD2, FAD3, FAD7 and low expression of gene LOX3.1, LOX3.2 contribute to the accumulation of α-linolenic acid.