title: Degradation of aromatic compounds through the β-ketoadipate pathway is required for pathogenicity of the tomato wilt pathogen Fusarium oxysporum f. sp. lycopersici.
abstract: Plant roots react to pathogen attack by the activation of general and systemic resistance, including the lignification of cell walls and increased release of phenolic compounds in root exudate. Some fungi have the capacity to degrade lignin using ligninolytic extracellular peroxidases and laccases. Aromatic lignin breakdown products are further catabolized via the β-ketoadipate pathway. In this study, we investigated the role of 3-carboxy-cis,cis-muconate lactonizing enzyme (CMLE), an enzyme of the β-ketoadipate pathway, in the pathogenicity of Fusarium oxysporum f. sp. lycopersici towards its host, tomato. As expected, the cmle deletion mutant cannot catabolize phenolic compounds known to be degraded via the β-ketoadipate pathway. In addition, the mutant is impaired in root invasion and is nonpathogenic, even though it shows normal superficial root colonization. We hypothesize that the β-ketoadipate pathway in plant-pathogenic, soil-borne fungi is necessary to degrade phenolic compounds in root exudate and/or inside roots in order to establish disease.
authors: Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands. c.b.michielse@uni-muenster.de
authors: Caroline B
authors: CB
authors: Michielse
authors: Linda
authors: L
authors: Reijnen
authors: Chantal
authors: C
authors: Olivain
authors: Claude
authors: C
authors: Alabouvette
authors: Martijn
authors: M
authors: Rep
mesh_terms: D000272:Adipates / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000187:drug effects; D015169:Colony Count, Microbial; D019597:Flax / Q000187:drug effects / Q000382:microbiology; D005670:Fusarium / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000472:pathogenicity*; D017353:Gene Deletion; D006841:Hydrocarbons, Aromatic / Q000378:metabolism* / Q000494:pharmacology; D019753:Intramolecular Lyases / Q000737:chemistry / Q000302:isolation & purification; D018551:Solanum lycopersicum / Q000187:drug effects / Q000382:microbiology*; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000382:microbiology*; D018517:Plant Roots / Q000187:drug effects / Q000382:microbiology; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development
chemical_list: D000272:Adipates; D006841:Hydrocarbons, Aromatic; C027316:3-oxoadipic acid; D019753:Intramolecular Lyases; C019831:3-carboxy-cis-cis-muconate cyclase