Non-canonical fungal G-protein coupled receptors promote Fusarium head blight on wheat
Fig 6
The Fusarium graminearum FGRRES_16221 mutant shows defects in establishing symptomless rachis node infection, resulting in apoplastic occlusions.
A) Images depict non-infected wheat describing the anatomy of the wheat spikelet (SP), rachis node (RN) and internode (RI) tissues. B) Light micrographs of transverse sections through the rachis node of the mock and PH-1 infected tissues at 9 days post infection. The healthy mock tissue shows the branching of the vasculature within the rachis node. 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. Note that PH-1 infection has already advanced multiple rachis nodes ahead. C) Light micrographs of transverse sections of the Δ16221_3 infected 3rd rachis node revealing the appearance of infection at the advancing hyphal front, plus ahead (+100 μm) and behind (-100 μm) the hyphal front. Behind the hyphal front, Δ16221_3 accumulates within intercellular spaces between a mixture of live and dead plant cells. At the hyphal front, a limited amount of intercellular hyphae are surrounded by active live plant cells. In advance of the hyphal front, the plant cells are responding to infection resulting in cell fortifications and the occlusion of the intercellular spaces. Arrows: grey = fungal hyphae, yellow = wheat cells responding to infection. Bar = 50 μm. P = parenchyma. V = vasculature.