title: General and species-specific transcriptional responses to downy mildew infection in a susceptible (Vitis vinifera) and a resistant (V. riparia) grapevine species.
abstract: BACKGROUND
  Downy mildew is a destructive grapevine disease caused by Plasmopara viticola (Berk. and Curt.) Berl. and de Toni, which can only be controlled by intensive fungicide treatments. Natural sources of resistance from wild grapevine (Vitis) species are used in conventional breeding approaches, but the signals and effectors involved in resistance in this important crop species are not well understood.
  
  
  RESULTS
  Early transcriptional changes associated with P. viticola infection in susceptible V. vinifera and resistant V. riparia plants were analyzed using the Combimatrix microarray platform. Transcript levels were measured 12 and 24 h post-inoculation, reflecting the time points immediately preceding the onset of resistance in V. riparia, as determined by microscopic analysis. Our data indicate that resistance in V. riparia is induced after infection, and is not based on differences in basal gene expression between the two species. The strong and rapid transcriptional reprogramming involves the induction of pathogenesis-related proteins and enzymes required for the synthesis of phenylpropanoid-derived compounds, many of which are also induced, albeit to a lesser extent, in V. vinifera. More interestingly, resistance in V. riparia also involves the specific modulation of numerous transcripts encoding components of signal transduction cascades, hypersensitive reaction markers and genes involved in jasmonate biosynthesis. The limited transcriptional modulation in V. vinifera represents a weak attempted defense response rather than the activation of compatibility-specific pathways.
  
  
  CONCLUSIONS
  Several candidate resistance genes were identified that could be exploited in future biotechnological approaches to increase disease resistance in susceptible grapevine species. Measurements of jasmonic acid and methyl jasmonate in infected leaves suggest that this hormone may also be involved in V. riparia resistance to P. viticola.
authors.affiliation: Department of Biotechnology, University of Verona, 37134 Verona, Italy.
authors.forename: Marianna
authors.initials: M
authors.lastname: Polesani
authors.forename: Luisa
authors.initials: L
authors.lastname: Bortesi
authors.forename: Alberto
authors.initials: A
authors.lastname: Ferrarini
authors.forename: Anita
authors.initials: A
authors.lastname: Zamboni
authors.forename: Marianna
authors.initials: M
authors.lastname: Fasoli
authors.forename: Claudia
authors.initials: C
authors.lastname: Zadra
authors.forename: Arianna
authors.initials: A
authors.lastname: Lovato
authors.forename: Mario
authors.initials: M
authors.lastname: Pezzotti
authors.forename: Massimo
authors.initials: M
authors.lastname: Delledonne
authors.forename: Annalisa
authors.initials: A
authors.lastname: Polverari
mesh_terms: D000085:Acetates / Q000378:metabolism; D003517:Cyclopentanes / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D054884:Host-Pathogen Interactions; D007113:Immunity, Innate; D020411:Oligonucleotide Array Sequence Analysis; D009868:Oomycetes / Q000472:pathogenicity*; D054883:Oxylipins / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D015398:Signal Transduction; D013045:Species Specificity; D014158:Transcription, Genetic; D027843:Vitis / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D054883:Oxylipins; D018749:RNA, Plant; C011006:jasmonic acid; C072239:methyl jasmonate