title: Identification of genes involved in fungal responses to strigolactones using mutants from fungal pathogens.
abstract: Strigolactones (SLs) as components of root exudates induce hyphal branching of arbuscular mycorrhizal (AM) fungi which is thought to favor the establishment of the beneficial symbiosis. Little is known on how AM fungi respond to SLs. Since AM fungi are poor model systems due to their obligate biotrophism and the lack of genetic transformation protocols, we took advantage of the sensitivity of several phytopathogenic fungi to GR24, a synthetic SLs analog. With the aim to identify the molecular determinants involved in SLs response in AM fungi and assuming conserved mechanisms in the fungal kingdom, we exploited the fungal pathogens Botrytis cinerea and Cryphonectria parasitica, for which mutant collections are available. Exposure of B. cinerea and C. parasitica to GR24 embedded in solid medium led to reduction of fungal radial growth. We set up the screening of a set of well-characterized gene deletion mutants to isolate genotypes with altered responses to SLs. Two B. cinerea mutants (defective of BcTrr1, a thioredoxin reductase and BcLTF1, a GATA transcription factor) turned out to be less responsive to GR24. One feature shared by the two mutants is the overproduction of reactive oxygen species (ROS). Indeed, an oxidizing effect was observed in a B. cinerea strain expressing a redox-sensitive GFP2 in the mitochondrial intermembrane space upon exposure to GR24. ROS and mitochondria are, therefore, emerging as mediators of SLs actions.
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Viale Mattioli 25, 10125, Turin, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Belmondo
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westf. Wilhelms-Universität Münster, Schlossplatz 8, 48143, Münster, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Marschall
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westf. Wilhelms-Universität Münster, Schlossplatz 8, 48143, Münster, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Tudzynski
authors.affiliation: Soil Microbiology and Symbiotic Systems' Estacion Experimental del Zaidin (CSIC), Profesor Albareda 1, 18008, Granada, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: López Ráez
authors.affiliation: Department of Chemistry, University of Torino, via Giuria 7, 10125, Turin, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Artuso
authors.affiliation: Department of Chemistry, University of Torino, via Giuria 7, 10125, Turin, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Prandi
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Viale Mattioli 25, 10125, Turin, Italy. luisa.lanfranco@unito.it.|Center for Molecular Systems Biology, University of Torino, Viale Mattioli 25, 10125, Turin, Italy. luisa.lanfranco@unito.it.
authors.forename: L
authors.initials: L
authors.lastname: Lanfranco
mesh_terms: D001203:Ascomycota / Q000235:genetics* / Q000254:growth & development; D020171:Botrytis / Q000235:genetics* / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D005656:Fungal Proteins / Q000235:genetics; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects*; D025301:Hyphae / Q000235:genetics / Q000254:growth & development; D007783:Lactones / Q000737:chemistry / Q000494:pharmacology*; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D015394:Molecular Structure; D009154:Mutation; D038821:Mycorrhizae / Q000235:genetics / Q000254:growth & development; D018517:Plant Roots / Q000737:chemistry / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013559:Symbiosis; D013997:Time Factors
chemical_list: D005656:Fungal Proteins; C507382:GR24 compound; D007783:Lactones; D017382:Reactive Oxygen Species
keywords: Botrytis cinerea; Cryphonectria parasitica; GR24; Mutant strains; Reactive oxygen species; Strigolactones