Quantitative trait loci conferring resistance to Fusarium head blight in barley respond differentially to Fusarium graminearum infection

Fusarium head blight (FHB), primarily caused by Fusarium graminearum, reduces grain yield and quality in barley. Resistance to FHB is partial and quantitatively inherited. Previously, major FHB resistant QTL were detected on barley chromosome 2H Bin 8 and 2H Bin 10, and another QTL for reduced deoxynivalenol (DON) accumulation was identified on chromosome 3H Bin 6. To develop an understanding of the molecular responses controlled by these loci, we examined DON and fungal biomass levels and the transcriptome differences in near-isogenic line (NIL) pairs carrying contrasting resistant and susceptible alleles at these QTL during F. graminearum infection. No overlap was found among the differentially accumulated transcripts of the three NIL pairs, indicating that the response to infection controlled by the resistance alleles at each QTL may be distinct. Transcripts showing differential accumulation between resistant and susceptible NILs were compared to results from previous wheat/barley-F. graminearum studies and integrated into a wheat/barley-F. graminearum interaction model.