SRA

Fusarium graminearum infects barley spikes and causes Fusarium head blight (FHB), a major disease problem worldwide. Resistance to FHB is partial and controlled by quantitative trait loci (QTL) of which two are located on barley chromosomes 2H bin8 (2Hb8) and 6H bin7 (6Hb7). To understand the molecular mechanisms of FHB resistance, transcriptomes of near-isogenic lines (NILs) carrying Chevron-derived resistant alleles for the two QTL and recurrent parents (M69 and Lacey) were investigated with RNA sequencing after F. graminearum or mock inoculation. A total of 2,083 FHB-responsive transcripts were detected and provide a gene expression atlas for the barley-F. graminearum interaction. Comparative analysis of the 2Hb8 resistant (R) NIL and M69 revealed that the 2Hb8 R NIL exhibited an elevated defense response in the absence of fungal infection and responded quicker than M69 upon fungal infection. The 6Hb7 R NIL displayed a more rapid induction of a set of defense genes than Lacey during the early stage of fungal infection. Overlap of differentially accumulated genes were identified between the two R NILs, suggesting that certain defense mechanisms may represent basal resistance to F. graminearum and/or general biotic stress response and were co-regulated by the two QTL. Long noncoding RNAs (lncRNAs) have emerged as potential key regulators of transcription. A total of 12,366 lncRNAs were identified of which 604 were FHB responsive. The current transcriptomic analysis revealed the differential mechanisms conferred by two QTL in response to F. graminearum infection and identified genes and lncRNAs that were associated with FHB resistance.