title: Trehalose synthesis and metabolism are required at different stages of plant infection by Magnaporthe grisea.
abstract: The relationship of trehalose metabolism to fungal virulence was explored in the rice blast fungus Magnaporthe grisea. To determine the role of trehalose synthesis in pathogenesis, we identified and deleted TPS1, encoding trehalose-6-phosphate synthase. A Deltatps1 mutant failed to synthesize trehalose, sporulated poorly and was greatly attenuated in pathogenicity. Appressoria produced by Deltatps1 did not develop full turgor or elaborate penetration hyphae efficiently. To determine the role of subsequent trehalose breakdown, we deleted NTH1, which encodes a neutral trehalase. Nth1 mutants infected plants normally, but showed attenuated pathogenicity due to a decreased ability to colonize plant tissue. A second trehalase was also identified, required both for growth on trehalose and mobilization of intracellular trehalose during infection-related development. TRE1 encodes a cell wall-localized enzyme with characteristics of both neutral and acidic trehalases, but is dispensable for pathogenicity. Our results indicate that trehalose synthesis, but not its subsequent breakdown, is required for primary plant infection by M.grisea, while trehalose degradation is important for efficient development of the fungus in plant tissue following initial infection.
authors.affiliation: School of Biological Sciences, University of Exeter, Washington Singer Laboratories, Perry Road, Exeter EX4 4QG, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Foster
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Jenkinson
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Talbot
mesh_terms: D000595:Amino Acid Sequence; D005656:Fungal Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D005800:Genes, Fungal; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D020082:Magnaporthe / Q000472:pathogenicity* / Q000502:physiology; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012275:Oryza / Q000382:microbiology*; D010641:Phenotype; D010802:Phylogeny; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014198:Trehalase / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism; D014199:Trehalose / Q000378:metabolism*; D014774:Virulence
chemical_list: D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D014199:Trehalose; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase; D014198:Trehalase