title: Involvement of OsJAZ8 in jasmonate-induced resistance to bacterial blight in rice.
abstract: The plant hormone jasmonic acid (JA) has a crucial role in both host immunity and development in plants. Here, we report the importance of JA signaling in the defense system of rice. Exogenous application of JA conferred resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) in rice. Expression of OsJAZ8, a rice jasmonate ZIM-domain protein, was highly up-regulated by JA. OsJAZ8 interacted with a putative OsCOI1, which is a component of the SCF(COI1) E3 ubiquitin ligase complex, in a coronatine-dependent manner. OsJAZ8 also formed heterodimers with other OsJAZ proteins but did not form homodimer. JA treatment caused OsJAZ8 degradation and this degradation was dependent on the 26S proteasome pathway. Furthermore, the JA-dependent OsJAZ8 degradation was mediated by the Jas domain. Transgenic rice plants overexpressing OsJAZ8ΔC, which lacks the Jas domain, exhibited a JA-insensitive phenotype. A large-scale analysis using a rice DNA microarray revealed that overexpression of OsJAZ8ΔC altered the expression of JA-responsive genes, including defense-related genes, in rice. Furthermore, OsJAZ8ΔC negatively regulated the JA-induced resistance to Xoo in rice. On the basis of these data, we conclude that JA plays an important role in resistance to Xoo, and OsJAZ8 acts as a repressor of JA signaling in rice.
authors.affiliation: Kagawa University, Miki, Kagawa, 761-0795 Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Yamada
authors.forename: Akihito
authors.initials: A
authors.lastname: Kano
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tamaoki
authors.forename: Ayumi
authors.initials: A
authors.lastname: Miyamoto
authors.forename: Hodaka
authors.initials: H
authors.lastname: Shishido
authors.forename: Seika
authors.initials: S
authors.lastname: Miyoshi
authors.forename: Shiduku
authors.initials: S
authors.lastname: Taniguchi
authors.forename: Kazuya
authors.initials: K
authors.lastname: Akimitsu
authors.forename: Kenji
authors.initials: K
authors.lastname: Gomi
mesh_terms: D003517:Cyclopentanes / Q000494:pharmacology*; D019281:Dimerization; D060467:Disease Resistance; D015870:Gene Expression; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000187:drug effects / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D054883:Oxylipins / Q000494:pharmacology*; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D055550:Protein Stability / Q000187:drug effects; D017434:Protein Structure, Tertiary; D059748:Proteolysis / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D020798:Two-Hybrid System Techniques; D015854:Up-Regulation / Q000187:drug effects; D014974:Xanthomonas / Q000502:physiology*
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; C011006:jasmonic acid; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease