title: The Constitutive Endopolygalacturonase TvPG2 Regulates the Induction of Plant Systemic Resistance by Trichoderma virens.
abstract: Trichoderma spp. are opportunistic fungi some of which are commonly present in the rhizosphere. Several species, such as T. virens, are also efficient biocontrol agents against phytopathogenic fungi and exert beneficial effects on plants. These effects are the consequence of interactions between Trichoderma and plant roots, which trigger enhanced plant growth and induce plant resistance. We have previously shown that T. virens I10 expresses two endopolygalacturonase genes, tvpg1 and tvpg2, during the interaction with plant roots; tvpg1 is inducible while tvpg2 is constitutively transcribed. Using the same system, the tomato polygalacturonase-inhibitor gene Lepgip1 was induced at the same time as tvpg1. Here we show by gene disruption that TvPG2 performs a regulatory role on the inducible tvpg1 gene and in triggering the plant immune response. A tvpg2-knockout strain fails to transcribe the inducible tvpg1 gene in neither in vitro in inducing media containing pectin or plant cell walls, nor during the in vivo interaction with tomato roots. Likewise, the in vivo induction of Lepgip1 does not occur, and its defense against the pathogen Botrytis cinerea is significantly reduced. Our data prove the importance of a T. virens constitutively produced endopolygalacturonase in eliciting plant induced systemic resistance against pathogenic fungi.
authors.affiliation: First, second, third, fourth, and seventh authors: Department of Agriculture, Food and Environment, University of Pisa, Italy, via del Borghetto 80, 56124 Pisa, Italy; fifth and sixth authors: Research Area Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, 1060 Vienna, Austria; and seventh author: Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Sarrocco
authors.affiliation: First, second, third, fourth, and seventh authors: Department of Agriculture, Food and Environment, University of Pisa, Italy, via del Borghetto 80, 56124 Pisa, Italy; fifth and sixth authors: Research Area Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, 1060 Vienna, Austria; and seventh author: Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy.
authors.forename: Fabiola
authors.initials: F
authors.lastname: Matarese
authors.affiliation: First, second, third, fourth, and seventh authors: Department of Agriculture, Food and Environment, University of Pisa, Italy, via del Borghetto 80, 56124 Pisa, Italy; fifth and sixth authors: Research Area Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, 1060 Vienna, Austria; and seventh author: Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy.
authors.forename: Riccardo
authors.identifier: http://orcid.org/0000-0002-5878-1159
authors.initials: R
authors.lastname: Baroncelli
authors.affiliation: First, second, third, fourth, and seventh authors: Department of Agriculture, Food and Environment, University of Pisa, Italy, via del Borghetto 80, 56124 Pisa, Italy; fifth and sixth authors: Research Area Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, 1060 Vienna, Austria; and seventh author: Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Vannacci
authors.affiliation: First, second, third, fourth, and seventh authors: Department of Agriculture, Food and Environment, University of Pisa, Italy, via del Borghetto 80, 56124 Pisa, Italy; fifth and sixth authors: Research Area Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, 1060 Vienna, Austria; and seventh author: Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy.
authors.forename: Verena
authors.initials: V
authors.lastname: Seidl-Seiboth
authors.affiliation: First, second, third, fourth, and seventh authors: Department of Agriculture, Food and Environment, University of Pisa, Italy, via del Borghetto 80, 56124 Pisa, Italy; fifth and sixth authors: Research Area Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, 1060 Vienna, Austria; and seventh author: Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy.
authors.forename: Christian Peter
authors.initials: CP
authors.lastname: Kubicek
authors.affiliation: First, second, third, fourth, and seventh authors: Department of Agriculture, Food and Environment, University of Pisa, Italy, via del Borghetto 80, 56124 Pisa, Italy; fifth and sixth authors: Research Area Biotechnology and Microbiology, Institute of Chemical Engineering, TU Wien, 1060 Vienna, Austria; and seventh author: Scuola Normale Superiore di Pisa, piazza dei Cavalieri 7, 56126 Pisa, Italy.
authors.forename: Mariarosaria
authors.initials: M
authors.lastname: Vergara
mesh_terms: D020171:Botrytis / Q000502:physiology*; D060467:Disease Resistance; D005656:Fungal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D018551:Solanum lycopersicum / Q000276:immunology / Q000382:microbiology*; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology*; D018517:Plant Roots / Q000276:immunology / Q000382:microbiology; D011096:Polygalacturonase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D059386:Reverse Genetics; D014242:Trichoderma / Q000201:enzymology* / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D011096:Polygalacturonase
keywords: gene knockout; polygalacturonase inhibiting proteins