Fig. 6: Cell type-specific function of Erc1.
From: A conserved enzyme of smut fungi facilitates cell-to-cell extension in the plant bundle sheath
a Microscopic observation of trapped Ustilago maydis infected maize leaf and tassel tissues via WGA-AF488/Propidium iodide staining. WGA-AF488 (green color indicates fungal cell wall): excitation at 488 nm and detection at 500-540 nm. PI (red color indicates bundle sheath cells): excitation at 561 nm and detection at 580–630 nm. Unlike leaf tissue, no bundle sheaths cells are detectable in tassel tissue. b Protoplastation of maize leaf cells. Pictures were taken after treatment with plant cell wall degrading enzymes. While the used enzyme mix has the ability to convert mesophyll cells into protoplasts, bundle sheath cells remain intact. c Schematic depiction of the biotrophic interface of host-smut interaction. Fungus-derived proteins are depicted in gray. During host colonization, 1,3-β-glucan molecules are accumulated at the biotrophic interface and Erc1 may hydrolyze these 1,3-β-glucans to prevent the accumulation and subsequent recognition of DAMP molecules by the host plant. d While wild-type smut fungi have the ability to move from cell-to-cell in bundle sheath cells, Δerc1 mutants do not have the ability to fully suppress host immunity leading to the described cell-arrest phenotype (Modified from Fig. 1c). e, f Aniline blue staining with maize leaf cross-section for detection of callose. Intensity of aniline blue signal is depicted via graph (e). Orange bars indicate bundle sheath cell wall, green bars indicate mesophyll cell wall. Similar results were observed in two independent biological experiments.
