title: Cloning and characterization of the erg1 gene of Trichoderma harzianum: effect of the erg1 silencing on ergosterol biosynthesis and resistance to terbinafine.
abstract: Trichoderma species are commonly used as biocontrol agents of different plant-pathogenic fungi. Terpene compounds are involved in the biocontrol process due to their antifungal properties (e.g., ergokonins and viridins) but additionally their structural function in the cell membranes (ergosterol) is essential. We report here the characterization of the T. harzianum erg1 gene, encoding a squalene epoxidase, a key enzyme in the biosynthesis of triterpene derivatives such as ergosterol. In T. harzianum the partial silencing of the erg1 gene gave rise to transformants with a higher level of sensitivity to terbinafine, an antifungal compound that acts specifically over the squalene epoxidase activity. In addition, these silenced transformants produced lower levels of ergosterol than the wild type strain. Finally, the silencing of the erg1 gene resulted in an increase in the expression level of the erg7 gene that encodes the oxidosqualene lanosterol-cyclase, another enzyme of the terpene biosynthesis pathway.
authors.affiliation: Spanish-Portuguese Center of Agricultural Research (CIALE), Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio Departamental lab 208, Spain.
authors.forename: R E
authors.initials: RE
authors.lastname: Cardoza
authors.forename: J A
authors.initials: JA
authors.lastname: Vizcaíno
authors.forename: M R
authors.initials: MR
authors.lastname: Hermosa
authors.forename: S
authors.initials: S
authors.lastname: Sousa
authors.forename: F J
authors.initials: FJ
authors.lastname: González
authors.forename: A
authors.initials: A
authors.lastname: Llobell
authors.forename: E
authors.initials: E
authors.lastname: Monte
authors.forename: S
authors.initials: S
authors.lastname: Gutiérrez
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D025141:Drug Resistance, Fungal / Q000235:genetics*; D004875:Ergosterol / Q000096:biosynthesis*; D015966:Gene Expression Regulation, Fungal; D020868:Gene Silencing; D005816:Genetic Complementation Test; D019751:Intramolecular Transferases / Q000235:genetics; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009281:Naphthalenes / Q000494:pharmacology*; D010802:Phylogeny; D012331:RNA, Fungal / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D050603:Squalene Monooxygenase / Q000235:genetics / Q000502:physiology*; D000077291:Terbinafine; D014158:Transcription, Genetic; D014242:Trichoderma / Q000187:drug effects / Q000235:genetics* / Q000502:physiology
chemical_list: D000935:Antifungal Agents; D004271:DNA, Fungal; D009281:Naphthalenes; D012331:RNA, Fungal; D012333:RNA, Messenger; D050603:Squalene Monooxygenase; D019751:Intramolecular Transferases; C021924:lanosterol synthase; D000077291:Terbinafine; D004875:Ergosterol