甘蓝型油菜Δ9硬脂酰ACP脱氢酶（SAD)基因的克隆与表达分析

为改良甘蓝型油菜菜籽油脂肪酸的组分，根据拟南芥Δ9硬脂酰ACP脱氢酶（SAD)核酸序列特征，检索白菜全基因组SAD基因和cDNA的可能序列，通过同源序列法克隆获得6个甘蓝型油菜SAD基因。比对结果显示，这6个基因编码的氨基酸序列同源性达53.2%~96.3%。系统进化分析显示，甘蓝型油菜SAD基因与蓖麻、大豆、芝麻、葵花等6个油料作物SAD基因的序列相似性很高，甘蓝型油菜与这些高等植物的SAD基因在进化上具有较高的保守性。本文还对4个甘蓝型油菜SAD基因BnSAD1:1、BnSAD2:1、BnSAD2:2和BnSAD2:3进行了表达模式分析，发现它们在种子发育过程中表达，并且都在40d的种子中表达量达到最高值，推测这4个基因均参与了硬脂酰ACP (C18:0-ACP)脱氢生成油酰基ACP(Δ9C18:1-ACP)的过程，尤其是BnSAD2:3可能为种子特异表达基因。

Stearoyl-acyl carrier protein desaturase (SAD) gene cloning and expression in Brassica napus

Abstract：In order to improve the components of fatty acids in rapeseed oil, 6 SAD genes of Brassica napus were retrieved by searching putative stearoyl-acyl carrier protein desaturase (SAD) genes from B.rapa genome according to the characteristic SAD genes of Arabidopsis thaliana. The results of sequence alignment showed that the similarity of the six SAD protein sequences of B. napus ranged from 53.2% to 96.3%. Phylogenetic analysis further showed that SAD genes of B. napus had high sequence similarity to those from Ricinus communis, Clycine max and Sasamum indicum etc., indicating that SAD genes of B. napus and other higher plants were highly conserved during evolution. We analyzed the expression patterns of BnSAD1:1, BnSAD2:1, BnSAD2:2 and BnSAD2:3, and found that all the 4 genes were expressed during the seed development, and the relative expression level of 4 genes were the highest at 40DAF (day after flower). It suggested that all these 4 genes involved in the formation of oleoyl-ACP derived from the dehydrogenation of stearoyl-ACP, and BnSAD2:3 gene was likely to express specifically in seed.