title: Investigation on the partial resistance of Cpkk2 knock out strain of Cryphonectria parasitica to Cryphonectria hypovirus 1 infection in presence of Geneticin and Geneticin resistance gene.
abstract: We have recently characterized the central components of the three MAP kinase cascades present in Cryphonectria parasitica : the MEK genes cpkk1, cpkk2 and cpkk3. When we attempted to infect through anastomosis the three knock out strains with Cryphonectria hypovirus 1 (CHV1), only the deletion strain of Cpkk2, the yeast Ste7 homologue, involved in mating and filamentous growth, could not be infected. We then proceeded to attempt virus infection through transformation of Δcpkk2 protoplasts using an infectious cDNA clone able to establish virus infection through transformation. In this case, a very limited number of strains could be recovered as stable transformants compared to the efficiency of control transformations with plasmid carrying only the antibiotic marker. Furthermore, transformants carrying actively replicating virus could be isolated only if the selection marker Geneticin was used during the very initial selection process, and not maintained throughout the growth of the colonies. Moreover, Δcpkk2 isolates that maintained the virus lost Geneticin resistance. We therefore unveiled a specific negative interaction among virus infection, presence of Geneticin in the growth media, and lack of Cpkk2 MEK in the fungal host.
authors.affiliation: Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, 10135 Torino, Italy. Electronic address: massimo.turina@ipsp.cnr.it.
authors.forename: Massimo
authors.initials: M
authors.lastname: Turina
authors.affiliation: Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, 10135 Torino, Italy.
authors.forename: Marika
authors.initials: M
authors.lastname: Rossi
authors.affiliation: Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, 10135 Torino, Italy.
authors.forename: Marino
authors.initials: M
authors.lastname: Moretti
mesh_terms: D001203:Ascomycota / Q000187:drug effects* / Q000235:genetics* / Q000821:virology*; D000067148:Fungal Viruses / Q000502:physiology*; D017353:Gene Deletion; D055786:Gene Knockout Techniques; D005800:Genes, Fungal; D005839:Gentamicins / Q000494:pharmacology*
chemical_list: D005839:Gentamicins; C010680:antibiotic G 418
keywords: Chestnut blight; Cryphonectria parasitica; Hypovirus; MAP Kinase; MEK; Virus resistance