花生转录因子基因NAC4的等位变异分析

摘要

NAC transcription factors play an important role in response to abiotic stress of plant. In this paper, bioinformatic analysis indicated that transcription factor geneAhNAC4(accession number HM776131.1) can response to drought signal. The comparison of cDNAs (ShrNAC4-a andShrNAC4-b) and genomic DNAs (ShNAC4-a andShNAC4-b) from Shanhua 11 showed thatAhNAC4 has a full length of 1244 bp and an ORF of 1050 bp, containing two introns at 182–279 bp and 547–642 bp, and encoding 349 amino acids. Four kinds ofAhNAC4 genes, named asAhNAC4-a1, AhNAC4-a2, AhNAC4-b1, andAhNAC4-b2(ab-breviations:a1, a2, b1, andb2), were cloned from 32 cultivars with different drought resistances. Among them a1 anda2 were alleles, with only one locus different between the two genes, leading to the difference of corresponding amino acids at site 174;b1 andb2 were alleles, with 14 SNPs, of which two SNPs led to differences of the corresponding amino acids at sites 174 and 244. There were four genotypes ofAhNAC4 in the 32 cultivars, containing 10a1a1b1b1, 5a1a1b2b2, 15a2a2b1b1, and 2a2a2b2b2. Meanwhile, 11NAC4 genes (Aw1NAC4–Aw11NAC4) were isolated from 19 wild peanut accessions inArachis.Aw2NAC4 had the highest homology of nucleotide sequence with a1 ora2, andb1 orb2 had the highest homology of nucleotide sequence with Aw1NAC4. It is speculated that the protein encodinga1 plays a key role in responding drought stress, and the function of the pro-teins encodinga1 andb1 genes is closer with that of wild species.%NAC 转录因子在植物应答非生物胁迫中起重要作用。利用生物信息学分析推测花生栽培种转录因子基因AhNAC4(登录号为 HM776131.1)属于抗旱相关转录因子基因,对比栽培品种山花11号 AhNAC4的2条 cDNA序列(ShrNAC4-a和ShrNAC4-b)及其相应的DNA序列(ShNAC4-a和ShNAC4-b)表明,AhNAC4全长为1244 bp,编码区长度为1050 bp,含有2个内含子,分别位于182~279 bp和547~642 bp处,编码蛋白包含349个氨基酸。从抗旱性不同的32个栽培品种分离得到4类AhNAC4,分别命名为AhNAC4-a1、AhNAC4-a2、AhNAC4-b1和AhNAC4-b2,缩写为a1、a2、b1和b2。a1和a2为等位基因,二者在717 bp处存在1个碱基差异,引起第174位氨基酸的改变,b1和b2为等位基因,二者存在14个SNP位点,其中717 bp和924 bp处碱基的差异引起第174位和第244位氨基酸的改变。供试品种中基因型为 a1a1b1b1、a1a1b2b2、a2a2b1b1、a2a2b2b2的品种数分别为10、5、15和2。从19个野生种中分离得到11类 NAC4的 DNA 序列(Aw1NAC4–Aw11NAC4), Aw1NAC4与栽培种 b1、b2的核苷酸序列同源性最高, Aw2NAC4与栽培种a1、a2核苷酸序列同源性最高。推测栽培种a1基因编码蛋白对花生抵御干旱起关键作用, a1和b1基因编码蛋白的功能与野生种更接近。