Dissecting the genetic basis of grain color and pre-harvest sprouting resistance in common wheat by association analysis
Shengnan Yan, Zhao-yu YU, Wei Gao, Xu-yang WANG, Jiajia Cao, Jie Lu, Chuanxi Ma, Cheng Chang, Haiping Zhang
Abstract
Pre-harvest sprouting (PHS) adversely affects wheat quality and yield. Grain color (GC) is associated with PHS resistance. However, the genetic relationship between grain color (GC) and PHS resistance remains unclear. In this study, 168 wheat varieties (lines) with significant differences in GC and PHS resistance were genotyped by Illumina 90K iSelect SNP array. Genome-wide association study (GWAS) based on a mixed linear model showed that 67 marker-trait associations (MTAs) assigned to 29 loci, including 17 potentially novel loci, were significantly associated with GC, which explained 1.1-17.0% of the phenotypic variation. In addition, 100 MTAs belonging to 54 loci, including 31 novel loci, were significantly associated with PHS resistance, which accounted for 1.1-14.7% of the phenotypic variation. Subsequently, two CAPS markers 2B-448 on chromosome 2B and 5B-301 on chromosome 5B were developed from the representative SNPs of major common loci Qgc. ahau-2B. 3/Qphs. ahau-2B. 4 controlling GC/PHS resistance and PHS resistance locus Qphs. ahau-5B. 4, respectively. Further validation in 171 Chinese mini-core collections confirmed significant correlations of the two CAPS markers with GC and PHS resistance phenotypes under different environments (P<0.05). Furthermore, the wheat public expression database, transcriptomic sequencing, and gene allelic variation analysis identified TraesCS5B02G545100 encoding glutaredoxin as a potential candidate gene linked to Qphs. ahau-5B. 4. A new CAPS marker CAPS-356 was then developed based on the SNP (T/C) in the CDS region of TraesCS5B02G545100. The high-density linkage map of the Jing 411/Hongmangchun 21 recombinant inbred lines (RILs) constructed based on specific locus amplified fragment sequencing markers showed that CAPS-356 collocated with a novel QTL for PHS resistance, supporting that TraesCS5B02G545100 is the potential candidate gene linked to Qphs. ahau-5B. 4. These results provide valuable information for the map-based cloning of Qphs. ahau-5B. 4 and breeding of PHS resistant white-grained varieties.