title: Sm2, a paralog of the Trichoderma cerato-platanin elicitor Sm1, is also highly important for plant protection conferred by the fungal-root interaction of Trichoderma with maize.
abstract: BACKGROUND
  The proteins Sm1 and Sm2 from the biocontrol fungus Trichoderma virens belong to the cerato-platanin protein family. Members of this family are small, secreted proteins that are abundantly produced by filamentous fungi with all types of life-styles. Some species of the fungal genus Trichoderma are considered as biocontrol fungi because they are mycoparasites and are also able to directly interact with plants, thereby stimulating plant defense responses. It was previously shown that the cerato-platanin protein Sm1 from T. virens - and to a lesser extent its homologue Epl1 from Trichoderma atroviride - induce plant defense responses. The plant protection potential of other members of the cerato-platanin protein family in Trichoderma, however, has not yet been investigated.
  
  
  RESULTS
  In order to analyze the function of the cerato-platanin protein Sm2, sm1 and sm2 knockout strains were generated and characterized. The effect of the lack of Sm1 and Sm2 in T. virens on inducing systemic resistance in maize seedlings, challenged with the plant pathogen Cochliobolus heterostrophus, was tested. These plant experiments were also performed with T. atroviride epl1 and epl2 knockout strains. In our plant-pathogen system T. virens was a more effective plant protectant than T. atroviride and the results with both Trichoderma species showed concordantly that the level of plant protection was more strongly reduced in plants treated with the sm2/epl2 knockout strains than with sm1/epl1 knockout strains.
  
  
  CONCLUSIONS
  Although the cerato-platanin genes sm1/epl1 are more abundantly expressed than sm2/epl2 during fungal growth, Sm2/Epl2 are, interestingly, more important than Sm1/Epl1 for the promotion of plant protection conferred by Trichoderma in the maize-C. heterostrophus pathosystem.
authors.affiliation: Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a, 1060, Vienna, Austria. romana.gaderer@tuwien.ac.at.
authors.forename: Romana
authors.initials: R
authors.lastname: Gaderer
authors.affiliation: Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel. nettali@tx.technion.ac.il.
authors.forename: Netta L
authors.initials: NL
authors.lastname: Lamdan
authors.affiliation: Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a, 1060, Vienna, Austria. alexa.frischmann@tuwien.ac.at.
authors.forename: Alexa
authors.initials: A
authors.lastname: Frischmann
authors.affiliation: Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences (BOKU), Vienna, Austria. michael.sulyok@boku.ac.at.
authors.forename: Michael
authors.initials: M
authors.lastname: Sulyok
authors.affiliation: Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences (BOKU), Vienna, Austria. rudolf.krska@boku.ac.at.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Krska
authors.affiliation: Department of Biology, Technion - Israel Institute of Technology, Haifa, Israel. horwitz@tx.technion.ac.il.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Horwitz
authors.affiliation: Research Division Biotechnology and Microbiology, Institute of Chemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a, 1060, Vienna, Austria. verena.seidl@tuwien.ac.at.
authors.forename: Verena
authors.initials: V
authors.lastname: Seidl-Seiboth
mesh_terms: D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D055786:Gene Knockout Techniques; D010935:Plant Diseases / Q000382:microbiology / Q000517:prevention & control; D018517:Plant Roots / Q000382:microbiology*; D036226:Seedlings / Q000276:immunology / Q000382:microbiology; D014242:Trichoderma / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D003313:Zea mays / Q000276:immunology* / Q000382:microbiology*
chemical_list: D005656:Fungal Proteins