title: A nonnative and a native fungal plant pathogen similarly stimulate ectomycorrhizal development but are perceived differently by a fungal symbiont.
abstract: The effects of plant symbionts on host defence responses against pathogens have been extensively documented, but little is known about the impact of pathogens on the symbiosis and if such an impact may differ for nonnative and native pathogens. Here, this issue was addressed in a study of the model system comprising Pinus pinea, its ectomycorrhizal symbiont Tuber borchii, and the nonnative and native pathogens Heterobasidion irregulare and Heterobasidion annosum, respectively. In a 6-month inoculation experiment and using both in planta and gene expression analyses, we tested the hypothesis that H. irregulare has greater effects on the symbiosis than H. annosum. Although the two pathogens induced the same morphological reaction in the plant-symbiont complex, with mycorrhizal density increasing exponentially with pathogen colonization of the host, the number of target genes regulated in T. borchii in plants inoculated with the native pathogen (i.e. 67% of tested genes) was more than twice that in plants inoculated with the nonnative pathogen (i.e. 27% of genes). Although the two fungal pathogens did not differentially affect the amount of ectomycorrhizas, the fungal symbiont perceived their presence differently. The results may suggest that the symbiont has the ability to recognize a self/native and a nonself/nonnative pathogen, probably through host plant-mediated signal transduction.
authors.affiliation: Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Zampieri
authors.affiliation: Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy.|Centre of Competence for the Innovation in the Agro-Environmental Field (AGROINNOVA), University of Torino, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy.
authors.forename: Luana
authors.initials: L
authors.lastname: Giordano
authors.affiliation: Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy.
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Lione
authors.affiliation: Department of Life Sciences and Systems Biology (DBIOS), University of Torino, Viale P.A. Mattioli 25, I-10125, Torino, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Vizzini
authors.affiliation: Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy.
authors.forename: Fabiano
authors.initials: F
authors.lastname: Sillo
authors.affiliation: Institute for Sustainable Plant Protection, CNR, Torino Unit, Viale P.A. Mattioli 25, I-10125, Torino, Italy.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Balestrini
authors.affiliation: Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Gonthier
mesh_terms: D001203:Ascomycota / Q000235:genetics / Q000502:physiology*; D001487:Basidiomycota / Q000502:physiology*; D016000:Cluster Analysis; D018506:Gene Expression Regulation, Plant; D008390:Markov Chains; D009010:Monte Carlo Method; D038821:Mycorrhizae / Q000502:physiology*; D028223:Pinus / Q000235:genetics / Q000382:microbiology*; D018547:Plant Stems / Q000382:microbiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000382:microbiology; D013559:Symbiosis
chemical_list: D012333:RNA, Messenger
keywords: 
  Heterobasidion
  ; 
  Pinus pinea
  ; 
  Tuber borchii
  ; RT-qPCR; biological invasions; gene expression; impact