Non-canonical fungal G-protein coupled receptors promote Fusarium head blight on wheat
Fig 7
The Fusarium graminearum mutant lacking FGRRES_16221 shows delayed rachis internode colonisation and vascular occlusions.
The delay in disease progression by the F. graminearum FGRRES_16221 mutant, in comparison to the parental PH-1 strain at 9 days post infection. Light micrographs of longitudinal sections of the 1st, 3rd and 5th rachis internode below the point of infection. In the 1st rachis internode, Δ16221_3 has established both inter- and intra-cellular infection, resulting in plant cell death and the destruction of the vasculature. In the 3rd rachis internode, Δ16221_3 has accumulated within the xylem vessel. This is the only infection beyond the apoplastic occlusion in the 3rd rachis node. In the 5th rachis internode, occlusions in the xylem vessels are observed ahead of infection. In contrast, the fully symptomatic PH-1 infected tissue shows the destruction of the wheat vasculature, the absence of live plant cells, and the presence of both inter- and intra-cellular fungal hyphae throughout the 1st, 3rd and 5th rachis internodes. Note rachis infection by the PH-1 strain has already progressed multiple rachis internodes ahead of infection by Δ16221_3. Arrows: grey = fungal hyphae, yellow = occlusions in the xylem vessel. Bar = 100 μm.