Abstract: 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.

Key words: Wheat, TaPK7 gene, Single nucleotide polymorphism, Drought tolerance, Haplotype