小麦钙网蛋白基因TaCRT-A多态性及其定位

Sequence polymorphism and mapping of wheat Ca^(2+)-binding protein TaCRT-A gene

以苗期抗旱性不同的37份六倍体普通小麦(AABBDD)、3份A基因组材料(AA)和3份四倍体小麦(AABB)为材料,通过直接测序法检测TaCRT-A基因的单核苷酸多态性,分析该基因多态性与小麦苗期抗旱性的关系,并进行遗传定位.结果表明:TaCRT-A基因DNA长度为3887bp,在总长度为167141bp的核苷酸序列中共检测到202个核苷酸变异位点,其中包括165个SNP和37个InDel,二者出现的频率分别为1/1013bp和1/4517bp.编码区的核苷酸多样性π值小于非编码区,编码区所承受的选择压力较大.43份试材可分为14种单倍型,其中H1、H2和H13分别含有普通小麦二倍体野生近缘种A基因组供体种的1份材料,H6、H7分别包含抗旱性极强的1份材料,H8包含四倍体波斯小麦并同时包含抗旱材料与干旱敏感材料,H11主要包括强抗旱材料与中等抗旱材料;虽然TaCRT受水分胁迫诱导表达,但TaCRT-A基因的结构多态性分析未能揭示其多态性与小麦苗期抗旱性之间的直接关系;利用RIL群体(Opata 85×W7984)将该基因定位于3A染色体标记Xmwg30～Xmwg570之间,遗传距离分别为10.5cM和49.6cM.

Taking thirty-seven hexaploid wheat（AABBDD） accessions with different drought resistance at seedling stage,three wheat species with A genome（AA）,and three tetraploid wheat species（AABB） as test materials,and by direct sequencing the single nucleotide polymorphism（SNP） in TaCRT-A,this paper analyzed the relationships of the SNP with the drought resistance of wheat（Triticum aestivum） at its seedling stage,and mapped the TaCRT-A on the chromosome of wheat.The full-length sequence of the TaCRT-A genomic DNA was 3887 bp.A total of 202 nucleotide variant loci were observed in the full length sequence of 167141 bp,among which,165 SNP and 37 InDel with the frequencies of 1 SNP/1013 bp and 1 InDel/4517 bp were detected,respectively.The nucleotide diversity（π） in coding region of TaCRT-A was lower than that in non-coding region,suggesting that the selection pressure in coding region was stronger than that in non-coding region.The 43 accessions could be classified as 14 haplotypes（H1-H14） by haploid analysis,among which,H1,H2,and H13 all contained one accession which was the donor species of A genome in common wheat,H6 and H7 had one high drought-resistant accession,H8 comprised tetraploid wheat,drought-resistant accessions,and drought-sensitive accessions,whereas H11 included the wheat accessions with drought-resistance and medium-drought resistance.Though the expression of TaCRT was induced by water stress,no significant relationship was identified between TaCRT-A polymorphism and drought resistance.Using a population of recombinant inbred lines derived from a cross of Opata 85×W7984,the TaCRT-A was mapped between SSR markers Xmwg30 and Xmwg570 on chromosome 3A,and the genetic distances were 10.5 cM and 49.6 cM from the flanking markers,respectively.