title: Production of trichodiene by Trichoderma harzianum alters the perception of this biocontrol strain by plants and antagonized fungi.
abstract: Trichothecenes are phytotoxic sesquiterpenic mycotoxins that can act as virulence factors in plant diseases. Harzianum A (HA) is a non-phytotoxic trichothecene produced by Trichoderma arundinaceum. The first step in HA biosynthesis is the conversion of farnesyl diphosphate to trichodiene (TD), a volatile organic compound (VOC), catalysed by a sesquiterpene synthase encoded by the tri5 gene. Expression of tri5 in the biocontrol strain Trichoderma harzianum CECT 2413 resulted in production of TD in parallel with a reduction of ergosterol biosynthesis and an unexpected increase in the level of squalene. Transformants expressing tri5 displayed low chitinase activity and induced expression of Botrytis cinerea BOT genes, although their total antagonistic potential against phytopathogenic fungi was not reduced. VOCs released by the tri5-transformant induced expression of tomato defence genes related to salicylic acid (SA), and TD itself strongly induced the expression of SA-responsive genes and reduced the development of lateral roots. Together, these results suggest that TD acts as a signalling VOC in the interactions of Trichoderma with plants and other microorganisms by modulating the perception of this fungus to a given environment. Moreover, the TD ability to induce systemic defences indicates that complex trichothecene structures may not be necessary for inducing such responses.
authors.affiliation: Area of Microbiology, Universitary School of Agricultural Engineers, University of León, Campus de Ponferrada, Avda. Astorga s/n, Ponferrada, 24400, Spain.
authors.forename: Mónica G
authors.initials: MG
authors.lastname: Malmierca
authors.affiliation: Bacterial Foodborne Pathogen and Mycology Unit, National Center for Agricultural Utilization Research, USDA/ARS, Peoria, IL, USA.
authors.forename: Susan P
authors.initials: SP
authors.lastname: McCormick
authors.affiliation: Area of Microbiology, Universitary School of Agricultural Engineers, University of León, Campus de Ponferrada, Avda. Astorga s/n, Ponferrada, 24400, Spain.
authors.forename: Rosa E
authors.initials: RE
authors.lastname: Cardoza
authors.affiliation: Bacterial Foodborne Pathogen and Mycology Unit, National Center for Agricultural Utilization Research, USDA/ARS, Peoria, IL, USA.
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Alexander
authors.affiliation: Spanish-Portuguese Centre of Agricultural Research (CIALE), Department of Microbiology and Genetics, University of Salamanca, Salamanca, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Monte
authors.affiliation: Area of Microbiology, Universitary School of Agricultural Engineers, University of León, Campus de Ponferrada, Avda. Astorga s/n, Ponferrada, 24400, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Gutiérrez
mesh_terms: D000898:Antibiosis; D020171:Botrytis / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D019755:Carbon-Carbon Lyases / Q000235:genetics / Q000378:metabolism; D004875:Ergosterol / Q000378:metabolism; D018551:Solanum lycopersicum / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology* / Q000517:prevention & control*; D020156:Salicylic Acid / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D014242:Trichoderma / Q000235:genetics / Q000378:metabolism*; D014255:Trichothecenes / Q000378:metabolism*; D055549:Volatile Organic Compounds / Q000378:metabolism
chemical_list: D014255:Trichothecenes; D055549:Volatile Organic Compounds; C087546:harzianum A; D019755:Carbon-Carbon Lyases; C051130:trichodiene synthetase; D020156:Salicylic Acid; D004875:Ergosterol