Non-canonical fungal G-protein coupled receptors promote Fusarium head blight on wheat
Fig 3
FGRRES_16221 receptor sub-domains are important to virulence.
A) The putative protein structure of GPCR FGRRES_16221, as predicted by the Phyre2 software [61], showing the presence of a cysteine-rich extracellular CFEM domain, plus the 3rd cytoplasmic loop (CL) and extended cytoplasmic tail (CT) potentially involved in interactions with downstream Gα-proteins. Schematic initially depicts the organisation of the native FGRRES_16221 protein and then shows the three FGRRES_16221 truncations generated. This includes ΔCFEM lacking the CFEM domain, ΔCT lacking the cytoplasmic tail and ΔTM3-7+CT lacking the majority of the protein (containing the 3rd cytoplasmic loop and cytoplasmic tail), leaving the extracellular CFEM domain tethered to the plasma membrane. In addition, the Δ16221_1 and Δ16221_3 mutants were both complemented with the native FGRRES_16221 gene. B) A boxplot showing the number of diseased spikelets at 15 days. The three types of FGRRES_16221 truncations all showed reduced disease symptoms on wheat at 15 days post infection (dpi). Truncations had a more severe impact on fungal virulence than the entire FGRRES_16221 gene deletion. Complementation of the Δ16221_1 and Δ16221_3 mutants (labelled—COM) restored fungal virulence to level equivalent to the parental PH-1 strain. *** = p<0.001, ** = p<0.01. C) The appearance of wheat disease symptoms at 15 dpi. Presented are two independent F. graminearum mutants of the deletion, truncation and complementation of the FGRRES_16221 receptor, compared to the parental PH-1 strain and the mock non-infected controls.