Fatty acid desaturase 2 (FAD2) is a crucial enzyme in the biosynthesis of polyunsaturated fatty acids in plants, which introduce a double bond into oleic acid to produce linoleic acid. FAD2 is imperative to the application and nutritional value of vegetable oil as both oleic acid and linoleic acid are the primary constituent fatty acids and their relative proportion determines the nutritional value and oxidative stability in most temperate vegetable oils. In the study described herein, we have identified a total of 253 candidate FAD2 genes from the published genomes of 79 plants. Phylogenetic analysis showed that FAD2 genes in green plants can be divided into three categories, namely, eudicots, monocots and lower plants (except Amborella trichopoda). Through the analysis of its conserved domains, all FAD2 genes contain motifs harbouring HECGH, HRRHH and HVAHH, −the three histidine clusters that are important functional structures of FAD2 gene. According to exon/intron structure analysis, the number of introns varies greatly in lower plants. With the evolution of green plants, the number of introns decreases. This study found that introns were mainly located in the 5’UTR and CDs regions, and their length ranged from 4 bp to 11,233 BP. In addition, about 56% of the 3 ‘and 5’ ends of FAD2 are located at Ag: GT, and the total content of a and t is generally about 60%.Through other bioinformatics methods, we concluded that FAD2 was more conservative in the process of plant evolution. This study provides theoretical support for further analysis of FAD2 gene family evolution.

脂肪酸去饱和酶2（FAD2）是植物中多不饱和脂肪酸生物合成中的关键酶，该酶将双键引入油酸中生成亚油酸。FAD2对植物油的应用和营养价值至关重要，因为油酸和亚油酸都是主要的脂肪酸成分，它们的相对比例决定了大多数温带植物油的营养价值和氧化稳定性。在本文所述的研究中，我们从已发表的79种植物基因组中鉴定出总共253个FAD2候选基因。系统发育分析表明，绿色植物中的FAD2基因可分为三类，即双子叶植物，单子叶植物和低等植物（除三叶草）。）。通过对其保守结构域的分析，所有FAD2基因均包含带有HECGH，HRRHH和HVAHH的基序，这三个基团簇是FAD2的重要功能结构基因。根据外显子/内含子结构分析，较低植物中内含子的数量差异很大。随着绿色植物的进化，内含子的数量减少。这项研究发现内含子主要位于5'UTR和CD区域，其长度在4 bp至11,233 BP之间。此外，FAD2的3'和5'末端约有56％位于Ag：GT，a和t的总含量通常约为60％。通过其他生物信息学方法，我们得出结论，FAD2在植物进化的过程。该研究为进一步分析FAD2基因家族进化提供了理论支持。