甜荞麦脂肪酸脱氢酶基因(FeFAD)家族的鉴定与分析

Genome-wide Identification and Bioinformatics Analysis of Fatty Acid Desaturase Gene(FeFAD)Family in Common Buckwheat

脂肪酸是人体内不可缺少的营养成分。虽然甜荞麦(Fagopyrum esculentum Moench)籽粒中油脂含量不高,但是研究表明其含有较高的多不饱和脂肪酸,不饱和脂肪酸含量在40%左右。脂肪酸脱氢酶(FAD)是形成不饱和脂肪酸的关键酶,甜荞麦脂肪酸脱氢酶基因的研究对理解其多不饱和脂肪酸的形成及调控具有重要意义。本研究利用甜荞麦基因组数据库,以拟南芥膜结合脂肪酸脱氢酶基因(FAD)作为种子序列进行Blastp序列比对,共鉴定出10个甜荞麦FAD全长基因,并对其基因特征、进化、保守结构域、蛋白质二级和三级结构等进行分析。结果显示:10个FeFAD基因被分为6个亚族;基因特征分析显示,FeFADs基因开放阅读框长度在900~1374 bp之间,等电点介于6.83~9.23之间;所有FeFAD基因均含有内含子,且FeFAD6的内含子数最多,含有10个内含子;除FeFAD4含有TMEM189_B_dmain结构域外,大多数FeFADs均含有保守的脂肪酸脱氢酶结构域,FeSLDs除含有脂肪酸脱氢酶结构域外还含有Cyt-b5特定结构域;除FeFAD4含有HXXXH、HXXHH 2个保守组氨酸序列外,其余FeFADs均含有HXXXH、HXXHH、HXXHH 3个保守组氨酸序列;二级结构氨基酸数量预测显示FeFADs均以α-螺旋和无规则卷曲为主;三级结构预测显示大多数FeFADs三级结构各自均有自身的独特结构。本研究结果将为探究甜荞麦脂肪酸脱氢酶基因的功能提供一定的理论依据。

Fatty acids are essential body nutrients.Although the content of oil in common buckwheat grain is not high,it contains high polyunsaturated fatty acids,and the content of unsaturated fatty acids is about 40%.Fatty acid desaturase(FAD)is a key enzyme for the formation of unsaturated fatty acids.The study of FAD genes in common buckwheat is important for understanding the formation and regulation of polyunsaturated fatty acids.In this study,a total of 10 full-length FAD genes were identified by Blastp from the common buckwheat genomic database by using the Arabidopsis membrane-bound fatty acid desaturase(FAD)genes as queries.The genetic characteristics,evolution,conserved domains,secondary and tertiary structure of proteins in common buckwheat FAD were analyzed.The results showed that 10 FeFAD genes were divided into 6 sub-groups.The analysis of gene characteristics showed that the open reading frame of FeFAD genes was among 900~1374 bp,and the isoelectric point was among 6.83~9.23.All FeFAD genes contain introns,and FeFAD6 contains the largest number of introns,which number is 10.FeFAD4 contains TMEM189_B_dmain conserved domain,whereas most FeFADs contain conserved fatty acid desaturase domains.FeSLDs contains not only fatty acid desaturase but also Cyt-b5 domain.Most FeFADs contain three conserved histidine sequences of HXXXH,HXXHH and HXXHH,except FeFAD4,which contains two conserved histidine sequences of HXXXH and HXXHH.The number of secondary amino acids predicted that FeFADs were mainlyα-helix and random coil.The prediction of tertiary structure shows that most of the tertiary structures of FeFADs have their own unique structures.The results of this study will provide a theoretical basis for exploring the function of fatty acid desaturase gene in common buckwheat.