title: Isolation of two aspartyl proteases from Trichoderma asperellum expressed during colonization of cucumber roots.
abstract: Trichoderma asperellum and cucumber seedlings were used as a model to study the modulation of Trichoderma gene expression during plant root colonization. Seedlings were grown in an aseptic hydroponics medium and inoculated with Trichoderma spore suspension. Proteins differentially secreted into the medium were isolated. Three major proteins of fungal origin were identified: two arabinofuranosidases (Abf1 and Abf2) and an aspartyl protease. Differential mRNA display was conducted on Trichoderma mycelia interacting and non-interacting, with the plant roots. Among the differentially regulated clones another aspartyl protease was identified. Sequencing of the genes revealed that the first aspartyl protease is a close homologue of PapA from T. harzianum and the other, of AP1 from Botryotinia fuckeliana. RT-PCR analysis confirms that the proteases are induced in response to plant roots attachment and are expressed in planta. papA, but not papB, is also induced in plate confrontation assays with the plant pathogen Rhizoctonia solani. These data suggest that the identified proteases play a role in Trichoderma both as a mycoparasite and as a plant opportunistic symbiont.
authors.affiliation: Department of Biological Chemistry, The Weizmann Institute of Science, 76100 Rehovot, Israel. ada.viterbo@weizmann.ac.il
authors.forename: Ada
authors.initials: A
authors.lastname: Viterbo
authors.forename: Michal
authors.initials: M
authors.lastname: Harel
authors.forename: Ilan
authors.initials: I
authors.lastname: Chet
mesh_terms: D000595:Amino Acid Sequence; D001203:Ascomycota / Q000235:genetics; D016282:Aspartic Acid Endopeptidases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D017124:Conserved Sequence; D018553:Cucumis sativus / Q000382:microbiology*; D004271:DNA, Fungal / Q000737:chemistry / Q000302:isolation & purification; D005656:Fungal Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D006026:Glycoside Hydrolases / Q000096:biosynthesis / Q000302:isolation & purification; D008969:Molecular Sequence Data; D025282:Mycelium / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000382:microbiology*; D012331:RNA, Fungal / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D012232:Rhizoctonia / Q000254:growth & development / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013559:Symbiosis; D014242:Trichoderma / Q000201:enzymology* / Q000254:growth & development
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D006026:Glycoside Hydrolases; C019713:alpha-N-arabinofuranosidase; D016282:Aspartic Acid Endopeptidases