title: Silencing of OPR3 in tomato reveals the role of OPDA in callose deposition during the activation of defense responses against Botrytis cinerea.
abstract: Cis-(+)-12-oxo-phytodienoic acid (OPDA) is likely to play signaling roles in plant defense that do not depend on its further conversion to the phytohormone jasmonic acid. To elucidate the role of OPDA in Solanum lycopersicum (tomato) plant defense, we have silenced the 12-oxophytodienoate reductase 3 (OPR3) gene. Two independent transgenic tomato lines (SiOPR3-1 and SiOPR3-2) showed significantly reduced OPR3 expression upon infection with the necrotrophic pathogen Botrytis cinerea. Moreover, SiOPR3 plants are more susceptible to this pathogen, and this susceptibility is accompanied by a significant decrease in OPDA levels and by the production of JA-Ile being almost abolished. OPR3 silencing also leads to a major reduction in the expression of other genes of the jasmonic acid (JA) synthesis and signaling pathways after infection. These results confirm that in tomato plants, as in Arabidopsis, OPR3 determines OPDA availability for JA biosynthesis. In addition, we show that an intact JA biosynthetic pathway is required for proper callose deposition, as its pathogen-induced accumulation is reduced in SiOPR3 plants. Interestingly, OPDA, but not JA, treatment restored basal resistance to B. cinerea and induced callose deposition in SiOPR3-1 and SiOPR3-2 transgenic plants. These results provide clear evidence that OPDA by itself plays a major role in the basal defense of tomato plants against this necrotrophic pathogen.
authors.affiliation: Grupo de Bioquímica y Biotecnología, Área de Fisiología Vegetal, Departament de Ciències Agràries i del Medi Natural, ESTCE, Universitat Jaume I, Castellón, 12071, Spain.
authors.forename: Loredana
authors.initials: L
authors.lastname: Scalschi
authors.forename: Maite
authors.initials: M
authors.lastname: Sanmartín
authors.forename: Gemma
authors.initials: G
authors.lastname: Camañes
authors.forename: Pilar
authors.initials: P
authors.lastname: Troncho
authors.forename: José J
authors.initials: JJ
authors.lastname: Sánchez-Serrano
authors.forename: Pilar
authors.initials: P
authors.lastname: García-Agustín
authors.forename: Begonya
authors.initials: B
authors.lastname: Vicedo
mesh_terms: D020171:Botrytis / Q000502:physiology*; D003979:Diazonium Compounds / Q000378:metabolism*; D005936:Glucans / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology*; D011725:Pyridines / Q000378:metabolism*
chemical_list: D003979:Diazonium Compounds; D005936:Glucans; D010940:Plant Proteins; D011725:Pyridines; C056727:2-(2'-pyridyldithio)benzyldiazoacetate; C048306:callose
keywords: Botrytis; OPDA; OPR3 silencing; callose; tomato plants