Non-canonical fungal G-protein coupled receptors promote Fusarium head blight on wheat
Fig 2
The discontinuous distribution of bona fide Fusarium graminearum non-classical G-protein coupled receptors.
A) Phylogenetics of putative F. graminearum GPCR encoding genes. The identification of FGRRES_16221 and FGRRES_07792 orthologues shows a discontinuous distribution throughout the fungal tree of life. Diagrammatic representation of the fungal tree of life (not indicative of evolutionary time) adapted from the JGI MycoCosm [52]. Pie charts show the number of species genomes within each taxonomic class with at least one FGRRES_16221 or FGRRES_07792 orthologue as predicted by PhytoPath [51]. The number of species genomes present in each group analysed is shown in brackets. * No Lecanoromycete genomes were represented in the PhytoPath dataset. Therefore, BlastP analyses using the mature FGRRES_07792 and FGRRES_16221 protein sequences were performed, at the expected (e-value) cut-off thresholds of 1x10-50 and 1x10-100, on the predicted proteomes of four Lecanoromycetes presented on the JGI Mycocosm portal [52]. B) A phylogenetic tree based on the alignment of the eight F. graminearum class X receptors, which possess the extracellular CFEM domain, with the original fungal class X receptor, PTH11 from Magnaporthae oryzae, labelled MoPTH11. C) Alignment of the CFEM domain from the eight F. graminearum class X GPCRs and MoPTH11, showing the conservation of the cysteine residues. * denotes Asp residue conserved in heme-binding CFEM proteins [34]. D) Left panel—Schematic depicts the yeast split ubiquitin approach for identification of receptor-G-protein interactions at the cell membrane. Right panel—Assay demonstrates class X non-classical (FGRRES_07792 and FGRRES_16221) receptors specifically interact with multiple Gα-proteins at the cell membrane. Yeast serial dilutions (1:1, 1:10, 1:100, 1:1000) were grown on non-selective SD media lacking tryptophan (T) and leucine (L), plus selective media also lacking histidine (H) and adenine (A). The Alg5 membrane protein is a non-GPCR interacting control.