title: Grape Marc Extract-Induced Defense Reactions and Protection against Phytophthora parasitica Are Impaired in NahG Tobacco Plants.
abstract: Grape marc extract (GME) acts as an elicitor of plant defense responses. This study analyzed GME-induced plant defense reactions in NahG transgenic tobacco. Leaf infiltration of NahG leaves revealed HR-like reactions with reduced lesions and weak deployment of autofluorescent compounds in the surrounding infiltrated tissues. The β-1,3-glucanase PR2-, endochitinase PR3-, and osmotin PR5-target transcript levels were strongly lowered in NahG leaves, and the mutant failed to accumulate the antimicrobial PR1 transcripts. GME-induced protection against Phytophthora parasitica var. nicotianae (Ppn) was evaluated on tobacco leaves. The antimicrobial properties of GME against Ppn were evidenced using a range of in vitro tests. GME-sprayed wild-type leaves showed reduced infection areas, whereas GME failed to induce a protective effect against Ppn in NahG leaves. The results suggest that GME-induced plant defense reactions in tobacco plants was mediated by salicylic acid (SA) and that GME-induced protection against Ppn could be the combined result of antimicrobial and defense actions.
authors.affiliation: †Clermont Université, Université Blaise Pascal, UMR 547 PIAF, B.P. 10448, Clermont-Ferrand, France.|‡INRA, UMR 547 PIAF, Clermont-Ferrand, France.
authors.forename: Razik
authors.initials: R
authors.lastname: Benouaret
authors.affiliation: †Clermont Université, Université Blaise Pascal, UMR 547 PIAF, B.P. 10448, Clermont-Ferrand, France.|‡INRA, UMR 547 PIAF, Clermont-Ferrand, France.
authors.forename: Pascale
authors.initials: P
authors.lastname: Goupil
mesh_terms: D005659:Fungicides, Industrial / Q000494:pharmacology*; D010838:Phytophthora / Q000187:drug effects* / Q000502:physiology; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology*; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000276:immunology / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D014026:Nicotiana / Q000187:drug effects* / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D027843:Vitis / Q000737:chemistry*
chemical_list: D005659:Fungicides, Industrial; D010936:Plant Extracts; D010940:Plant Proteins
keywords: NahG; Phytophthora parasitica; grape marc extract; protection; salicylic acid