An abiotic stress response gene TaSnRK2.7-B in wheat accessions: genetic diversity analysis and gene mapping based on SNPs

TaSnRK2.7, a SnRK2 (sucrose non-fermenting1-related protein kinase 2) member of wheat, confers enhanced multi-stress tolerance in carbohydrate metabolism. Here, the nucleotide diversity of TaSnRK2.7 was investigated in 60 wheat accessions with different stress-tolerant features. One copy, named TaSnRK2.7-B, was detected in 32 accessions, which mainly exhibited stress tolerance. The TaSnRK2.7-B evolutionary dynamics were examined in these cultivars, which have been subjected to population bottlenecks and intensive selection in breeding. Nucleotide diversity (π) in the entire TaSnRK2.7-B region was 0.00148. Sliding-window analysis demonstrated that 3932-4535bp was a variation-enriched region, covering the eighth intron, the ninth exon and the 3'-flanking region. As predicted, neutrality tests revealed that the TaSnRK2.7-B protein was relatively conservative, and population bottlenecks or purifying selection may have acted on TaSnRK2.7-B. Furthermore, linkage disequilibrium between SNP loci extends across the entire TaSnRK2.7-B region. A SNP marker of TaSnRK2.7-B was developed and mapped on chromosome 2AL flanked by WMC179.4 and WMC401, which were co-located in the same or adjacent chromosome intervals with QTLs for phosphorus utilization efficiency and accumulation efficiency of stem water-soluble carbohydrates.