BackgroundFusarium head blight (FHB), caused mainly by Fusarium graminearum (Fg) Schwabe (teleomorph: Gibberellazeae Schwble), brings serious damage to wheat production. Chinese wheat landrace Wangshuibai is one of the most important resistance sources in the world. The knowledge of mechanism underlying its resistance to FHB is still limited.ResultsTo get an overview of transcriptome characteristics of Wangshuibai during infection by Fg, a high-throughput RNA sequencing based on next generation sequencing (NGS) technology (Illumina) were performed. Totally, 165,499 unigenes were generated and assigned to known protein databases including NCBI non-redundant protein database (nr) (82,721, 50.0%), Gene Ontology (GO) (38,184, 23.1%), Swiss-Prot (50,702, 30.6%), Clusters of orthologous groups (COG) (51,566, 31.2%) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) (30,657, 18.5%), as determined by Blastx search. With another NGS based platform, a digital gene expression (DGE) system, gene expression in Wangshuibai and its FHB susceptible mutant NAUH117 was profiled and compared at two infection stages by inoculation of Fg at 24 and 48 hour, with the aim of identifying genes involved in FHB resistance.ConclusionPathogen-related proteins such as PR5, PR14 and ABC transporter and JA signaling pathway were crucial for FHB resistance, especially that mediated by Fhb1. ET pathway and ROS/NO pathway were not activated in Wangshuibai and may be not pivotal in defense to FHB. Consistent with the fact that in NAUH117 there presented a chromosome fragment deletion, which led to its increased FHB susceptibility, in Wangshuibai, twenty out of eighty-nine genes showed changed expression patterns upon the infection of Fg. The up-regulation of eight of them was confirmed by qRT-PCR, revealing they may be candidate genes for Fhb1 and need further functional analysis to confirm their roles in FHB resistance.

The SGT1 protein is essential for R protein-mediated and PAMPs-triggered resistance in many plant species. Here we reported the isolation and characterization of the Hv-SGT1 gene from Haynaldia villosa (2n = 14, VV). Analysis of the subcellular location of Hv-SGT1 by transient expression of a fusion to GFP indicated its presence in the cytoplasm and nucleus. Levels of Hv-SGT1 transcripts were increased by inoculation with either the biotrophic pathogen Blumeria graminis DC. f. Sp. tritici (Bgt) or the hemi-biotrophic pathogen Fusarium graminearum (Fg). Levels of Hv-SGT1 showed substantial increase following treatment with H2O2 and methyl jasmonate (MeJA), only slightly induced following exposure to ethephon or abscisic acid, but not changed following exposure to salicylic acid. The demonstration that silencing of Hv-SGT1 substantially reduced resistance to Bgt indicated that Hv-SGT1 was an essential component of disease resistance in H . villosa . The over-expression of Hv-SGT1 in Yangmai 158 enhanced resistance to powdery mildew, and this correlated with increased levels of whole-cell reactive oxygen intermediates at the sites of penetration by the pathogens. Compared with wild-type plants, the expression levels of genes related to the H2O2 and JA signaling pathways were lower in the Hv-SGT1 silenced plants and higher in the Hv-SGT1 over-expressing plants. Therefore, the involvement of Hv-SGT1 in H2O2 production correlates with the hypersensitive response and jasmonic acid signaling. Our novel demonstration that wheat with over-expressed Hv-SGT1 showed enhanced resistance to both powdery mildew and FHB suggests that it could served as a transgenic genetic resource in wheat breeding for multiple disease resistance.