Transcriptome analysis of wheat and barley near-isogenic line pairs carrying contrasting alleles for different Fusarium head blight resistance QTLs.

Abstract

Fusarium head blight (FHB), caused primarily by Fusarium graminearum, is a major disease problem on wheat and barley around the world. Grain yield and quality are reduced due to infection and the accumulation of trichothecene mycotoxins such as deoxynivalenol (DON). Previously, quantitative trait loci (QTL) conferring FHB resistance and reduced DON accumulation have been identified on wheat and barley chromosomes. A major FHB resistance QTL (Fhb1) was identified on wheat chromosome 3BS. Two major QTLs associated with reduced FHB severity have been detected on barley chromosome 2H Bin 8 and 2H Bin 10, which are associated with heading date and spike type, respectively. A QTL associated with reduced deoxynivalenol (DON) accumulation was identified on chromosome 3H Bin 6. Near-isogenic line (NIL) pairs carrying the resistant and susceptible allele for a wheat QTL and three barley QTL were used to examine DON concentration, fungal biomass and transcript accumulation during F. graminearum infection. Based on the disease phenotypes, transcript accumulation data, and comparative analysis of the wheat and barley host response to F. graminearum infection, we developed an integrated model for the wheat and barley-F. graminearum interactions. In addition, gene transcripts that are differentially expressed in the NIL pairs during infection provide a set of genes that may play a role in FHB resistance.