Nucleolar GTP-Binding Protein 1-2 (NOG1-2) Interacts with Jasmonate-ZIMDomain Protein 9 (JAZ9) to Regulate Stomatal Aperture during Plant Immunity

Abstract

Plant defense responses at stomata and apoplast are the most important early events during plant–bacteria interactions. The key components of stomatal defense responses have not been fully characterized. A GTPase encoding gene, NOG1-2, which is required for stomatal innate immunity against bacterial pathogens, was recently identified. Functional studies in Arabidopsis revealed that NOG1-2 regulates guard cell signaling in response to biotic and abiotic stimulus through jasmonic acid (JA)- and abscisic acid (ABA)-mediated pathways. Interestingly, in this study, Jasmonate-ZIM-domain protein 9 (JAZ9) was identified to interact with NOG1-2 for the regulation of stomatal closure. Upon interaction, JAZ9 reduces GTPase activity of NOG1-2. We explored the role of NOG1-2 binding with JAZ9 for COI1-mediated JA signaling and hypothesized that its function may be closely linked to MYC2 transcription factor in the regulation of the JA-signaling cascade in stomatal defense against bacterial pathogens. Our study provides valuable information on the function of a small GTPase, NOG1-2, in guard cell signaling and early plant defense in response to bacterial pathogens.

Plant Hormone Signaling Crosstalks between Biotic and Abiotic Stress Responses

“…A virulent strain of Pseudomonas syringae then injects the phytotoxin, coronatine (COR), which mimics the action of jasmonic acid–isoleucine (JA–ILeu), which is the active form of JA, into the host plant, in order to stimulate the re-opening of the stomata. COR, thus termed an effector, functions by stimulating the biosynthesis of JA via Jai1 , which in turn induces JA–ILeu-inducible wound-responsive genes via the transcription factor, MYC2, while repressing PATHOGENESIS-RELATED ( PR ) genes [ 48 , 49 , 50 ]. Thus, the wounding response becomes activated at the expense of defense response.…”

“…A small GTPase protein, NOG1-2, stimulates stomatal closure during abiotic stresses, and the nog1-2 mutant of Nicotiana benthamiana is more susceptible to the pathogen Pseudomonas syringae , due to its inability to close its stomata [ 55 ], proving its role in the re-closing of stomata opened by Pseudomonas syringae . NOG1-2-mediated stomatal closure is stimulated in the presence of COR, indicating that its function is dependent on JA–Ileu [ 48 ]. In Arabidopsis, JAZ9 is the protein that interacts with MYC2 and COI1 through its JA-associated (Jas) domain [ 56 ].…”

“…JAZ 9 also interacts with NOG1-2 through this same domain, and by binding to JAZ9, NOG1-2 interrupts the interaction between JAZ9 and COI1 and prevents JAZ9 from being targeted for degradation. Thus, JAZ9 can perform its role in inhibiting wounding response (i.e., stomatal re-opening) upon bacterial infection as part of the pathway in effector-triggered immunity (ETI) [ 48 ].…”

Transcriptome analysis reveals underlying immune response mechanism of fungal (Penicillium oxalicum) disease in Gastrodia elata Bl. f. glauca S. Chow (Orchidaceae)

“…f. glauca were probably the member of transcription factor families like WRKY, GH3, TIFY/JAZ, CML, ERF, TGA. Coincidently, it has been reported that above transcription factors did be widely involved in various defense responses [58,[90][91][92][93][94][95][96][97][98][99][100][101][102]. It is reported that GH3 and CML can also regulates fruit development [103,104].…”

Transcriptome analysis reveals underlying immune response mechanism of fungal (Penicillium oxalicum) disease in Gastrodia elata Bl. f. glauca S. Chow (Orchidaceae)

“…f. glauca were probably the member of transcription factor families like WRKY, GH3, TIFY/JAZ, CML, ERF, TGA. Coincidently, it has been reported that above transcription factors did be widely involved in various defense responses [26,[66][67][68][69][70][71][72][73][74][75][76][77][78]. It is reported that GH3 and CML can also regulates fruit development [79,80].…”