title: Involvement of Trichoderma trichothecenes in the biocontrol activity and induction of plant defense-related genes.
abstract: Trichoderma species produce trichothecenes, most notably trichodermin and harzianum A (HA), by a biosynthetic pathway in which several of the involved proteins have significant differences in functionality compared to their Fusarium orthologues. In addition, the genes encoding these proteins show a genomic organization differing from that of the Fusarium tri clusters. Here we describe the isolation of Trichoderma arundinaceum IBT 40837 transformants which have a disrupted or silenced tri4 gene, a gene encoding a cytochrome P450 monooxygenase that oxygenates trichodiene to give rise to isotrichodiol, and the effect of tri4 gene disruption and silencing on the expression of other tri genes. Our results indicate that the tri4 gene disruption resulted in a reduced antifungal activity against Botrytis cinerea and Rhizoctonia solani and also in a reduced ability to induce the expression of tomato plant defense-related genes belonging to the salicylic acid (SA) and jasmonate (JA) pathways against B. cinerea, in comparison to the wild-type strain, indicating that HA plays an important function in the sensitization of Trichoderma-pretreated plants against this fungal pathogen. Additionally, the effect of the interaction of T. arundinaceum with B. cinerea or R. solani and with tomato seedlings on the expressions of the tri genes was studied.
authors.affiliation: Area of Microbiology, Universitary School of Agricultural Engineers. University of León, Campus de Ponferrada, Ponferrada, Spain.
authors.forename: M G
authors.initials: MG
authors.lastname: Malmierca
authors.forename: R E
authors.initials: RE
authors.lastname: Cardoza
authors.forename: N J
authors.initials: NJ
authors.lastname: Alexander
authors.forename: S P
authors.initials: SP
authors.lastname: McCormick
authors.forename: R
authors.initials: R
authors.lastname: Hermosa
authors.forename: E
authors.initials: E
authors.lastname: Monte
authors.forename: S
authors.initials: S
authors.lastname: Gutiérrez
mesh_terms: D000935:Antifungal Agents / Q000378:metabolism* / Q000494:pharmacology; D020171:Botrytis / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D017343:Genes, Plant; D018551:Solanum lycopersicum / Q000276:immunology / Q000382:microbiology*; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D012232:Rhizoctonia / Q000187:drug effects; D014242:Trichoderma / Q000378:metabolism*; D014255:Trichothecenes / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D005656:Fungal Proteins; D014255:Trichothecenes; D003577:Cytochrome P-450 Enzyme System