Non-canonical fungal G-protein coupled receptors promote Fusarium head blight on wheat
Fig 8
RNA-sequencing reveals the role of FGRRES_16221 in coordinating fungal metabolism and virulence factors to promote infection without activating inhibitory wheat defences.
Wheat tissues sampled for RNA-sequencing to evaluate transcriptional differences in the pathogen and host during the infection establishment (spikelet, 3 day post infection; dpi) and the progression of infection (spikelet and sequential rachis internode pairs at 7 dpi). A) The ratio of wheat-to-fungal transcripts reflected differences in fungal burden, confirming the reduced progression of infection by the FGRRES_16221 mutant (Δ16221_3). B) The number of differentially expressed F. graminearum and wheat genes (DEGs; FDR <0.05, ±1log2 fold change in expression) identified in pairwise analyses between the parental PH-1 and Δ16221_3 during axenic culture and wheat infection. Overrepresented gene ontologies (GO) were identified within the DEGs and specific gene categories associated with pathogenesis (S1–S3 Files). Accumulative FPKM expression values for selected gene categories from F. graminearum (C) and wheat (D). Note absolute FPKM values presented for single FGL1 gene. Legend: YPD = axenic culture in YPD, SP_3d = spikelet 3 dpi, SP_7d = spikelet 7 dpi, R1-8_7d = pooled pairs of rachis internodes below inoculated spikelet at 7 dpi. E) Schematic representation of wheat infection by the parental PH-1 strain and the dysregulation of virulence mechanisms in the absence of FGRRES_16221. Green = live wheat cells. Yellow = Dead wheat cells. Brown = Wheat defence response including cell reinforcements, plus apoplastic and vascular occlusions. Purple = Invading F. graminearum hyphae.