title: Colletotrichum higginsianum extracellular LysM proteins play dual roles in appressorial function and suppression of chitin-triggered plant immunity.
abstract: The genome of the hemibiotrophic anthracnose fungus, Colletotrichum higginsianum, encodes a large repertoire of candidate-secreted effectors containing LysM domains, but the role of such proteins in the pathogenicity of any Colletotrichum species is unknown. Here, we characterized the function of two effectors, ChELP1 and ChELP2, which are transcriptionally activated during the initial intracellular biotrophic phase of infection. Using immunocytochemistry, we found that ChELP2 is concentrated on the surface of bulbous biotrophic hyphae at the interface with living host cells but is absent from filamentous necrotrophic hyphae. We show that recombinant ChELP1 and ChELP2 bind chitin and chitin oligomers in vitro with high affinity and specificity and that both proteins suppress the chitin-triggered activation of two immune-related plant mitogen-activated protein kinases in the host Arabidopsis. Using RNAi-mediated gene silencing, we found that ChELP1 and ChELP2 are essential for fungal virulence and appressorium-mediated penetration of both Arabidopsis epidermal cells and cellophane membranes in vitro. The findings suggest a dual role for these LysM proteins as effectors for suppressing chitin-triggered immunity and as proteins required for appressorium function.
authors.affiliation: Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, 50829, Cologne, Germany.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takahara
authors.affiliation: Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, 50829, Cologne, Germany.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Hacquard
authors.affiliation: Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands.
authors.forename: Anja
authors.initials: A
authors.lastname: Kombrink
authors.affiliation: Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, 50829, Cologne, Germany.
authors.forename: H Bleddyn
authors.initials: HB
authors.lastname: Hughes
authors.affiliation: Chemical Biology Laboratory, Max-Planck-Institute for Plant Breeding Research, 50829, Cologne, Germany.
authors.forename: Vivek
authors.initials: V
authors.lastname: Halder
authors.affiliation: UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850, Thiverval-Grignon, France.
authors.forename: Guillaume P
authors.initials: GP
authors.lastname: Robin
authors.affiliation: Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, 50829, Cologne, Germany.
authors.forename: Kei
authors.initials: K
authors.lastname: Hiruma
authors.affiliation: Central Microscopy, Max-Planck-Institute for Plant Breeding Research, 50829, Cologne, Germany.
authors.forename: Ulla
authors.initials: U
authors.lastname: Neumann
authors.affiliation: Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki, 214-8571, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Shinya
authors.affiliation: Chemical Biology Laboratory, Max-Planck-Institute for Plant Breeding Research, 50829, Cologne, Germany.
authors.forename: Erich
authors.initials: E
authors.lastname: Kombrink
authors.affiliation: Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki, 214-8571, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Shibuya
authors.affiliation: Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands.
authors.forename: Bart P H J
authors.identifier: 0000-0003-4125-4181
authors.initials: BP
authors.lastname: Thomma
authors.affiliation: Department of Plant-Microbe Interactions, Max-Planck-Institute for Plant Breeding Research, 50829, Cologne, Germany.|UMR BIOGER, INRA, AgroParisTech, Université Paris-Saclay, 78850, Thiverval-Grignon, France.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: O'Connell
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000276:immunology* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002686:Chitin / Q000494:pharmacology*; D002688:Chitinases / Q000378:metabolism; D020231:Colletotrichum / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D005110:Extracellular Space / Q000737:chemistry*; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005800:Genes, Fungal; D025301:Hyphae / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D057865:Plant Immunity / Q000187:drug effects*; D034622:RNA Interference; D014158:Transcription, Genetic / Q000187:drug effects; D014774:Virulence / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D005656:Fungal Proteins; D002686:Chitin; D002688:Chitinases
keywords: Arabidopsis; Colletotrichum; LysM; appressoria; biotrophy; chitin; effector; virulence