Expression of the 12-Oxophytodienoic Acid 10,11-Reductase Gene in the Compatible Interaction between Pea and Fungal Pathogen

Abstract

;Suppressors produced by Mycosphaerella pinodes are glycopeptides to block pea defense responses induced by elicitors. A clone, S64, was isolated as cDNA for suppressorinducible gene from pea epicotyls. The treatment of pea epicotyls with suppressor alone induced an increase of S64 mRNA within 1 h, and it reached a maximum level at 3 h after treatment. The induction was not affected by application of the elicitor, indicating that the suppressor has a dominant action to regulate S64 gene expression. S64 was also induced by inoculation with a virulent pathogen, M. pinodes, but not by inoculation with a non-pathogen, Ascochyta rabiei, nor by treatment with fungal elicitor. The deduced structure of S64 showed high homology to 12-oxophytodienoic acid reductase (OPR) in Arabidopsis thaliana. A recombinant protein derived from S64 had OPR activity, suggesting compatibility-specific activation of the octadecanoid pathway in plants. Treatment with jasmonic acid (JA) or methyl jasmonic acid, end products of the octadecanoid pathway, inhibited the elicitor-induced accumulation of PAL mRNA in pea. These results indicate that the suppressor-induced S64 gene expression leads to the production of JA or related compounds, which might contribute to the establishment of compatibility by inhibiting the phenylpropanoid biosynthetic pathway.

Structure and expression of 12-oxophytodienoate reductase (subgroup I) genes in pea, and characterization of the oxidoreductase activities of their recombinant products

“…Isolation and structural analysis of genomic loci harboring OPR-like genes in pea By screening the pea genomic DNA library with DIGlabeled S64 cDNA (Ishiga et al 2002) as a probe, we obtained four independent positive clones (clones 6, 10-6, 6-2 and 4-10), as shown in Fig. 1A.…”

“…To isolate cDNA clones corresponding to OPR-like genomic clones, we screened a cDNA library constructed from suppressortreated pea epicotyls (Ishiga et al 2002) by PCR. Corresponding cDNA clones were also isolated by the RT-PCR method using total RNA prepared from pea epicotyls that had been treated with 100 lM jasmonic acid or 12-OPDA for 3 h. PCR conditions are described in Table 1.…”

“…sequence of its predicted product indicates that S64 encodes a 12-oxophytodienoic acid reductase (OPR) and that recombinant S64 protein produced in bacteria possesses NADPH-dependent reductase activity for 2-CyHE (2-cyclohexen-1-one) and a racemic mixture of 12-oxophytodienoic acid (OPDA) (Ishiga et al 2002).…”

Bacterial Cyclic β-(1,2)-Glucan Acts in Systemic Suppression of Plant Immune Responses

“…To be successful, a pathogen must overcome or evade constitutive defenses and suppress or fail to elicit induced defenses (Bushnell and Rowell, 1981;Jackson et al, 1999;Bouarab et al, 2002;Ishiga et al, 2002;Hauck et al, 2003;Abramovitch and Martin, 2004;Keshavarzi et al, 2004;Abramovitch et al, 2006a). In phytopathogenic bacteria, effector proteins delivered by the type III secretion system and the toxin coronatine have been identified as suppressors of induced defenses (Cui et al, 2005;Abramovitch et al, 2006aAbramovitch et al, , 2006bJanjusevic et al, 2006;Melotto et al, 2006;Nomura et al, 2006).…”

Función del gen 3-cetoacil-CoA tiolasa 2 (KAT2) en defensa y desarrollo. Participación de los peroxisomas en las respuestas a herida en Arabidopsis thaliana.

“…Dentro del peroxisoma, se produce la reducción del cis-(+)-OPDA al correspondiente ácido 3-oxo-2(2´(Z)-pentenil)-ciclopentano-1-octanoico (OPC:8) por la enzima OPDA reductasa (OPR). Se han caracterizado enzimas OPR en varias especies vegetales (Schaller y Weiler, 1997;Schaller et al, 1998;Biesgen y Weiler, 1999;Costa et al, 2000;Ishiga et al, 2002;Agrawal et al, 2003;Sobajima et al, 2003;Matsui et al, 2004Tani et al, 2008) y en Arabidopsis y tomate, únicamente la isoforma OPR3 se localiza dentro de peroxisomas y presenta la correcta estereoespecificidad para producir la reacción (Müssig et al, 2000;Schaller et al, 2000;Strassner et al, 2002), correlacionando la deficiencia en el gen OPR3 con una menor cantidad de JA (Sanders et al, 2000;Stintzi y Browse, 2000). En los pasos finales de la biosíntesis, las aproximaciones bioquímicas realizadas habían determinado la esencialidad de tres rondas sucesivas de β-oxidación para acortar la cadena del OPC:8 (Vick y Zimmerman, 1983;Schaller, 2001;Feussner y Wasternack, 2002).…”