红花ω6脂肪酸脱氢酶基因克隆及生物信息学分析  

Cloning and bioinformatics analysis of omega-6 fatty acid desaturase genes in safflower(Carthamus tinctorius L.)

作　　者：官玲亮[1,2] 侯凯[1] 刘千[1] 邹宇婷[1] 易斌[1] 吴卫[1] 

机构地区：[1]四川农业大学农学院,四川成都611130 [2]中国热带农业科学院,热带作物品种资源研究所,海南儋州571737

出　　处：《中国油料作物学报》2013年第4期372-383,共12页Chinese Journal of Oil Crop Sciences

基　　金：国家自然科学基金(181274020)

摘　　要：采用RT-PCR和RACE(rapid amplification of cDNA ends)技术,从红花未成熟的种子和叶片中分离到8个FAD2基因和1个FAD6基因片段,并全部提交至GenBank上。在NCBI中Blast结果显示,CtFAD2-1和Ct-FAD2-8与向日葵、大豆、棉花等种子特异表达的FAD2-1基因的同源性较高。而CtFAD2-2与其他作物中组成型表达的FAD2-2/CtFAD2-3有较高的相似性。将红花ω6脂肪酸脱氢酶氨基酸序列进行同源性比对,CtFAD2-1与CtFAD2-8的同源性最高,为79.9%;其次是CtFAD2-2与CtFAD2-1和CtFAD2-8,分别为70.8%和70.2%;而这3个FAD2基因与其余5个拷贝间的序列相似性均较低,在52.0%～61.0%之间;CtFAD6与CtFAD2之间的相似性极低,在18.0%～21.9%之间。红花8个FAD2均检测到内质网滞留信号,将其定位于内质网膜上,而CtFAD6 N-端检测到67bp的质体信号肽序列,将其定位于叶绿体膜上。疏水性和跨膜分析结果显示,除Ct-FAD2-6以外,其余FAD2均含有6个疏水区,分别跨膜4～6次。Eight different microsomal ω6 fatty acid desaturases and one plastidial ω6 fatty acid desaturase cDNA sequences,designated CtFAD2-1,CtFAD2-2,CtFAD2-3,CtFAD2-4,CtFAD2-5,CtFAD2-6,CtFAD2-7,CtFAD2-8 and CtFAD6 have been isolated from safflower(Carthamus tinctorius L.) by using PCR.All of the deduced amino acid sequences showed three histidine boxes characteristic of all membrane-bound desaturases,and CtFAD2 contained a C-terminal ER retrieval motif,while CtFAD6 possessed a putative N-terminal signal peptide.Our Blast searches of the deduced amino acid sequences revealed that CtFAD2-1 and CtFAD2-8 showed higher similarities to other plant seed-type microsomal ω6 fatty acid desaturases,whereas CtFAD2-2 showed higher similarities to constitutively–expressed type.The other safflower microsomal ω6 fatty acid desaturase genes showed much lower identities to plant FAD2.The CtFAD6 showed higher similarity with other plant plastidial ω6 fatty acid desaturases.Hydropathy analysis showed that the encoded polypeptide contains six putative membrane-spanning domains.Transmembrane analysis indicated that all the safflower fatty acid desaturases contained four to six putative membrane-spanning domains except CtFAD6,Protein second-structure indicated that safflower ω6 fatty acid desaturase is mainly composed of α-helix and β-sheet.

关 键 词：红花 ω6脂肪酸脱氢酶 RT-RACE 亚油酸 

分 类 号：S565.903[农业科学—作物学]