甘蓝型油菜乙酰辅酶A羧化酶(ACCase)基因SNP分析

Single Nucleotide Polymorphism Analysis of ACCase Gene in Brassica napus L.

为了解甘蓝型油菜材料乙酰辅酶A羧化酶（ACCase）基因单核甘酸多态性及其与含油量的关系,该文采用高、低含油量的自交纯合系材料各6份,克隆了其同质型ACCase基因,经双向测序后用DNASTAR软件进行CLUSTAL分析,并用DNASP软件进行SNP多态性计算.结果表明：在供试材料共88 824bp的基因组核苷酸序列中共检测到317个SNPs,出现频率为1/279;其中发生在编码区的SNP有179个,非编码区138个;ACCase基因编码区的变异小于非编码区;非同义突变平均数（Ka）与同义突变平均数（Ks）比值小于1,表明该基因比较保守.在高含油量材料组中发现了一个明显高于低含油量材料的突变热点区,位于5 000~6 500bp（即全基因序列的第10 088到11 588bp）之间,该突变热点区包含了4个外显子和3个内含子,编码同质型ACCase的第1 279到1 648位共368个氨基酸的序列,这段序列位于生物素羧基载体蛋白（BCCP）与羧基转移酶（CT）功能域之间.此变异区域与ACCase活性及含油量的关系值得进一步研究.

To understand the single nucleotide polymorphism distribution of the acetyl CoA carboxylase（ACCase）gene of inbred homozygous oilseed rape（Brassica napus L.）lines and its relationship with oil content,the homomeric ACCase gene of six high and low oil-content lines each was cloned and bidirectionally sequenced.SNP markers were identified with CLUSTAL in DNASTAR package and SNP distribution analyses were carried out with DNASP software.Multi-alignment of the 12ACCase sequences of B.napus showed 317SNPs in 88,824bp total gene sequence,with an SNP frequency of 1/279,of which 179SNPs were in the coding region and 138in the non-coding region.The SNP frequency in the coding region of ACCase was lower than that in the non-coding region and the value of Ka/Ks was less than 1,suggesting the conservative nature of this gene.In sharp contrast to the low-oil content group,a high-frequency variation region was identified in the high-oil group.This region was found to be about 1500bp in length,corresponding to 10 088~11 588bp of the complete gene of ACCase,and cover 4exons（from 27to 30）and 3 introns（from 27to 29）.The involved 368amino acid residues between 1 279to 1 648were between the biotin carboxyl carrier protein（BCCP）domain and the carboxyl transferase（CT）domain of the homomeric ACCase.The relationship of this high-frequency variation region with ACCase activity and oil content is well worthy of further investigation.