title: Methionine elicits H2O2 generation and defense gene expression in grapevine and reduces Plasmopara viticola infection.
abstract: Methionine (Met) is a nutritionally essential sulfur-containing amino acid (SAA) known for its preponderant role as initiator in protein synthesis. However, other functions for Met in plants are not well described. The implication of this SAA in oxidative stress tolerance has been recently reported, however the mode of action of Met is still poorly understood. Here, we analyzed the elicitor activity of Met in grapevine as well as its effect on Plasmopara viticola resistance. The results show that Met induces hydrogen peroxide (H2O2) generation, a key element in plant defense signaling, and upregulates the expression of a battery of defense-related genes. Transcript levels of these genes were not further modulated by P. viticola inoculation of Met-pretreated plants, suggesting an elicitor role rather than a priming role for Met in grapevine. Met treatment also reduces P. viticola development in grapevine plants grown under glasshouse controlled-conditions. Fungitoxicity assays revealed that Met possesses a moderate antifungal activity compared with cysteine (Cys), another SAA known for its toxic effect to a large spectrum of fungi.
authors.affiliation: Unité Mixte de Recherche 1131, Université de Strasbourg, INRA - Colmar, 28 Rue de Herrlisheim, F68021 Colmar, France; Laboratoire de Physiologie Moléculaire des Plantes, Centre de Biotechnologie de Borj-Cédria, 2050 Hammam-Lif, Tunisia. Electronic address: hatem.boubakri@cbbc.rnrt.tn.
authors.forename: Hatem
authors.initials: H
authors.lastname: Boubakri
authors.forename: Mohamed Ali
authors.initials: MA
authors.lastname: Wahab
authors.forename: Julie
authors.initials: J
authors.lastname: Chong
authors.forename: Claude
authors.initials: C
authors.lastname: Gertz
authors.forename: Samia
authors.initials: S
authors.lastname: Gandoura
authors.forename: Ahmed
authors.initials: A
authors.lastname: Mliki
authors.forename: Christophe
authors.initials: C
authors.lastname: Bertsch
authors.forename: Isabelle
authors.initials: I
authors.lastname: Soustre-Gacougnolle
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology; D003545:Cysteine / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008715:Methionine / Q000494:pharmacology*; D009868:Oomycetes / Q000187:drug effects / Q000502:physiology*; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics; D027843:Vitis / Q000166:cytology / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology
chemical_list: D000935:Antifungal Agents; D008715:Methionine; D006861:Hydrogen Peroxide; D003545:Cysteine
keywords: AAs; AdoMet; Cys; Defense genes; Elicitation; H(2)O(2); HPI; HPT; Met; Methionine; Msr; PR; Plasmopara viticola; ROS; SAAs; SCC; Vitis vinifera; adenosylmethionine; amino acids; cysteine; hours post-inoculation; hours post-treatment; hydrogen peroxide; methionine; methionine sulfoxide reductases; pathogenesis related; reactive oxygen species; sulfur amino acids; suspension cultured cells