小麦TaPK7基因单核苷酸多态性与抗旱性的关系

以抗旱性不同的45份六倍体小麦和5份小麦的二倍体近缘种为材料, 通过测序检测TaPK7基因的单核苷酸多态性, 研究了TaPK7基因多态性与抗旱性的关系, 旨在为发掘利用小麦抗旱基因资源奠定基础。50份材料TaPK7序列总长220 448 bp, 其中有64个SNP和9个InDel, 二者的频率分别为1 SNP/3 445 bp和1 InDel/24 494 bp。编码区的核苷酸多样性π值小于非编码区, 可能是由于编码区承受的选择压力较大。同义突变(Ka)与非同义突变(Ks)比值是0.415, 表明该基因受负向选择影响, 属于相对保守基因。在编码区检测到16个单核苷酸突变, 多存在于抗旱材料中。共检测到21种单倍型, 其中5种为强抗旱材料单倍型, 2种为干旱极敏感材料单倍型, 11种中等抗旱材料单倍型, 另外3种单倍型中同时包括抗旱材料和干旱敏感材料, 初步揭示了TaPK7基因的单核苷酸多态性与抗旱性相关。

Relationship between Single Nucleotide Polymorphism of TaPK7 Gene a nd Drought Tolerance in Wheat

Protein phosphorylation/dephosphorylation are major signaling events induced by abiotic stresses in higher plants. Sucrose nonfermenting1-related protein kinase2 (SnRK2), which belongs to serine-threonine protein kinase, plays an important role in the process of sugar signal transduction. It is reported that the gene family is activated by hyperosmotic stress and relays the stress signal via phosphorylation. TaPK7 gene, a member of SnRK2 gene family of wheat (Triticum aestivum L.), is involved in the response to osmostic stress, such as drought, high salt, low temperature, and ABA treatment in wheat seedlings. To investigate the relationship between single nucleotide polymorphism (SNP) in TaPK7 and drought tolerance, 45 hexaploid wheat accessions and 5 diploid species of wheat relatives were used to detect SNP of TaPK7 through sequencing. Sixty four SNP and nine InDel were detected in a total of 220 448 bp nucleotide acids, and the frequencies of SNP and InDel were 1 SNP /3 445 bp and 1 InDel /24 494 bp, respectively. The nucleotide diversity value in non-coding region was higher than that in coding region, which suggested that the coding region suffered stronger selection pressure than non-coding region. Ka/Ks value of TaPK7 was 0.415, which indicated that TaPK7 was a conservative gene. Sixteen SNPs were observed in coding region, and most of them happed in drought-tolerant accessions. A total of 21 haplotypes were identified from the plant materials. Among them, 7 haplotypes of TaPK7 were only related to accessions with drought-tolerant or drought-sensitive characteristics, 11 haplotypes contained me-dium-drought-tolerant accessions, but 3 haplotypes contained both types of accessions. SNPs in TaPK7 were correlative with drought tolerance, but it couldn’t explain the mechanism of drought tolerance completely in wheat.