A wheat 1-FEH w3 variant underlies enzyme activity for stem WSC remobilization to grain under drought

• In wheat stems, levels of fructan-dominated water soluble carbohydrates (WSC) do not always correlate well with grain yield. • Field experiments were carried out to further elucidate this relationship. Westonia, Kauz and ~20 genetically diverse double haploid (DH) lines derived from them were investigated. • Substantial genotypic differences in fructan remobilization were found. • The results of enzyme activity and gene expression studies confirmed the major contribution of 1-FEH w3 in the process of stem fructan remobilization. • A Single Nucleotide Polymorphism (SNP) was detected in an auxin response element in the promoter region of 1-FEH w3 and the mutated Westonia allele might affect gene expression and enzyme activity levels. • The mutated Westonia allele of 1-FEH w3 was associated with a higher thousand grain weight (TGW) under drought in 2011 and 2012. • A Cleaved Amplified Polymorphic (CAP) marker was generated from the SNP. • These results indicate that higher gene expression of 1-FEH w3 and 1-FEH w3 mediated enzyme activities favour stem WSC remobilization to the grains. The CAP marker residing in the 1-FEH w3 promoter may facilitate wheat breeding, by selecting lines with high stem fructan remobilization capacity under terminal drought.status: publishe