title: Enhanced defense responses in Arabidopsis induced by the cell wall protein fractions from Pythium oligandrum require SGT1, RAR1, NPR1 and JAR1.
abstract: The cell wall protein fraction (CWP) is purified from the non-pathogenic biocontrol agent Pythium oligandrum and is composed of two glycoproteins (POD-1 and POD-2), which are structurally similar to class III elicitins. In tomato plants treated with CWP, jasmonic acid (JA)- and ethylene (ET)-dependent signaling pathways are activated, and resistance to Ralstonia solanaceraum is enhanced. To dissect CWP-induced defense mechanisms, we investigated defense gene expression and resistance to bacterial pathogens in Arabidopsis thaliana ecotype Col-0 treated with CWP. When the leaves of Col-0 were infiltrated with CWP, neither visible necrosis nor salicylic acid (SA)-responsive gene (PR-1 and PR-5) expression was induced. In contrast, JA-responsive gene (PDF1.2 and JR2) expression was up-regulated and the resistance to R. solanaceraum and Pseudomonas syringae pv. tomato DC3000 was enhanced in response to CWP. Such CWP-induced defense responses were completely compromised in CWP-treated coi1-1 and jar1-1 mutants with an impaired JA signaling pathway. The induction of defense-related gene expression after CWP treatment was partially compromised in ET-insensitive ein2-1 mutants, but not in SA signaling mutants or nahG transgenic plants. Global gene expression analysis using cDNA array also suggested that several other JA- and ET-responsive genes, but not SA-responsive genes, were up-regulated in response to CWP. Further analysis of CWP-induced defense responses using another eight mutants with impaired defense signaling pathways indicated that, interestingly, the induction of JA-responsive gene expression and enhanced resistance to two bacterial pathogens in response to CWP were completely compromised in rar1-1, rar1-21, sgt1a-1, sgt1b (edm1) and npr1-1 mutants. Thus, the CWP-induced defense system appears to be regulated by JA-mediated and SGT1-, RAR1- and NPR1-dependent signaling pathways.
authors.affiliation: Department of Life Science, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kawamura
authors.forename: Shigehito
authors.initials: S
authors.lastname: Takenaka
authors.forename: Shu
authors.initials: S
authors.lastname: Hase
authors.forename: Mayumi
authors.initials: M
authors.lastname: Kubota
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ichinose
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kanayama
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nakaho
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Klessig
authors.forename: Hideki
authors.initials: H
authors.lastname: Takahashi
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000737:chemistry*; D003517:Cyclopentanes / Q000378:metabolism / Q000494:pharmacology; D005030:Ethylenes / Q000378:metabolism / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D009713:Nucleotidyltransferases / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D054883:Oxylipins / Q000378:metabolism / Q000494:pharmacology; D010935:Plant Diseases / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D044224:Pseudomonas syringae / Q000472:pathogenicity; D011775:Pythium / Q000737:chemistry*; D018749:RNA, Plant / Q000378:metabolism; D043367:Ralstonia / Q000472:pathogenicity; D020156:Salicylic Acid / Q000378:metabolism / Q000494:pharmacology; D015398:Signal Transduction; D010453:Peptide Synthases
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D003517:Cyclopentanes; D005030:Ethylenes; D005964:Glucosyltransferases; D047908:Intracellular Signaling Peptides and Proteins; D009713:Nucleotidyltransferases; D054883:Oxylipins; D018749:RNA, Plant; D020156:Salicylic Acid; C105496:NPR1 protein, Arabidopsis; C499581:PBS2 protein, Arabidopsis; C011006:jasmonic acid; C036216:ethylene; C515668:SGT1 protein, Arabidopsis; C412831:AT2G46370 protein, Arabidopsis; D010453:Peptide Synthases