title: Trichoderma virens, a plant beneficial fungus, enhances biomass production and promotes lateral root growth through an auxin-dependent mechanism in Arabidopsis.
abstract: Trichoderma species belong to a class of free-living fungi beneficial to plants that are common in the rhizosphere. We investigated the role of auxin in regulating the growth and development of Arabidopsis (Arabidopsis thaliana) seedlings in response to inoculation with Trichoderma virens and Trichoderma atroviride by developing a plant-fungus interaction system. Wild-type Arabidopsis seedlings inoculated with either T. virens or T. atroviride showed characteristic auxin-related phenotypes, including increased biomass production and stimulated lateral root development. Mutations in genes involved in auxin transport or signaling, AUX1, BIG, EIR1, and AXR1, were found to reduce the growth-promoting and root developmental effects of T. virens inoculation. When grown under axenic conditions, T. virens produced the auxin-related compounds indole-3-acetic acid, indole-3-acetaldehyde, and indole-3-ethanol. A comparative analysis of all three indolic compounds provided detailed information about the structure-activity relationship based on their efficacy at modulating root system architecture, activation of auxin-regulated gene expression, and rescue of the root hair-defective phenotype of the rhd6 auxin response Arabidopsis mutant. Our results highlight the important role of auxin signaling for plant growth promotion by T. virens.
authors.affiliation: Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, CP 58030 Morelia, Michoacan, Mexico.
authors.forename: Hexon Angel
authors.initials: HA
authors.lastname: Contreras-Cornejo
authors.forename: Lourdes
authors.initials: L
authors.lastname: Macías-Rodríguez
authors.forename: Carlos
authors.initials: C
authors.lastname: Cortés-Penagos
authors.forename: José
authors.initials: J
authors.lastname: López-Bucio
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D018533:Biomass; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007210:Indoleacetic Acids / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D007211:Indoles / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D018517:Plant Roots / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development* / Q000382:microbiology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D036226:Seedlings / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000382:microbiology; D014242:Trichoderma / Q000502:physiology*; D000438:Alcohols
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D007210:Indoleacetic Acids; D007211:Indoles; D011993:Recombinant Fusion Proteins; C520580:RHD6 protein, Arabidopsis; C001655:indole-3-acetaldehyde; C005949:tryptophol; D000438:Alcohols; C030737:indoleacetic acid