Flg22 regulates MAP kinase 6 interaction with an ethylene response factor substrate via ethylene
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ABSTRACT: Despite their importance, plant MAP kinase targets are still poorly elucidated. Here, the specific in vivo interaction of an ethylene response factor (ERF104) with the Arabidopsis MAP kinase, MPK6, is shown by fluorescence resonance energy transfer. The interaction, which is lost within minutes after treatment with the flagellin-derived flg22 peptide, is dependent on both MPK6 kinase activity and rapid ethylene signaling initiated downstream of MPK6 activation. ERF104 is an MPK6 substrate and phosphorylation site mutations affected its stability. ERF104 activates promoters with GCC elements. This was evident from microarray data of overexpressing transgenic plants, where promoters of up regulated genes contain GCC motifs and chromatin immunoprecipitation showing ERF104 association with PDF1.2 promoter. The ERF104 overexpressor did not affect biotrophic bacteria proliferation but was more susceptible to necrotrophic Botrytis cinerea. Microarray performed with erf104 or mpk6 revealed only a limited number of flg22-induced genes that require these elements - possibly as a result of functional redundancies. Thus, ERF104 phosphorylation by MPK6, in concert with ethylene signaling induced by pathogen-derived molecules, modulates defense in Arabidopsis.
Project description:Despite their importance, plant MAP kinase targets are still poorly elucidated. Here, the specific in vivo interaction of an ethylene response factor (ERF104) with the Arabidopsis MAP kinase, MPK6, is shown by fluorescence resonance energy transfer. The interaction, which is lost within minutes after treatment with the flagellin-derived flg22 peptide, is dependent on both MPK6 kinase activity and rapid ethylene signaling initiated downstream of MPK6 activation. ERF104 is an MPK6 substrate and phosphorylation site mutations affected its stability. ERF104 activates promoters with GCC elements. This was evident from microarray data of overexpressing transgenic plants, where promoters of up regulated genes contain GCC motifs and chromatin immunoprecipitation showing ERF104 association with PDF1.2 promoter. The ERF104 overexpressor did not affect biotrophic bacteria proliferation but was more susceptible to necrotrophic Botrytis cinerea. Microarray performed with erf104 or mpk6 revealed only a limited number of flg22-induced genes that require these elements - possibly as a; result of functional redundancies. Thus, ERF104 phosphorylation by MPK6, in concert with ethylene signaling induced by pathogen-derived molecules, modulates defense in Arabidopsis. Experiment Overall Design: Leaves of six week old Col-0, erf104, mpk6 and 35S::ERF104 plants were infiltrated with 1µM Flg22 or water and harvested four hours later. Total RNA was isolated and processed according to the Affymetrix protocol for biotin-labelled cRNA and hybridized to the Affymetrix ATH1 chip. The data Experiment Overall Design: was analyzed with Genespring GX 7.3.1 software (Agilent) with the following parameters: Filter on Flags for present or marginal in 50% of all considered experiments, Filter for reliable differentially expressed genes based on volcano plot (one way ANOVA p-value <0.05 and >3-fold change in expression). For the flg22 experiments, analysis for each genotype was separately performed and a composite list of flg22-regulated genes compiled â with the aim of including genes that may be differentially regulated in the genotype. Global expression profile was visualized by k-means clustering and condition tree (Genespring).
Project description:au08-06_mpk6_heat_stressed - au08-06_mpk6_heat_stressed - Mitogen Activated Protein Kinase (MAPK) signaling pathways are key regulators of cell proliferation, differentiation and stress effectors. The core of the MAP kinase signal transduction cascade is composed of a three-kinase module consisting of a MAP kinase kinase kinase (MAPKKK), a MAP kinase kinase (MAPKK), and a MAP kinase (MAPK). The signaling pathway is activated upon stimulation by a phosphorylation cascade. In previous studies, it was shown that the mpk6 KO mutant plants are significantly more tolerant to heat stress in comparison to wt and that after 3h treatment at 37°C, an activation of heat-shock proteins occures in the mpk6 mutant. To better understand the changes occuring in the mpk6 mutant upon heat stress at the gene expression level, we would like to perform a microarray transcriptomic analysis. - Mitogen Activated Protein Kinase (MAPK) signaling pathways are key regulators of cell proliferation, differentiation and stress effectors. The core of the MAP kinase signal transduction cascade is composed of a three-kinase module consisting of a MAP kinase kinase kinase (MAPKKK), a MAP kinase kinase (MAPKK), and a MAP kinase (MAPK). The signaling pathway is activated upon stimulation by a phosphorylation cascade. In previous studies, it was shown that the mpk6 KO mutant plants are significantly more tolerant to heat stress in comparison to wt and that after 3h treatment at 37°C, an activation of heat-shock proteins occures in the mpk6 mutant. To better understand the changes occuring in the mpk6 mutant upon heat stress at the gene expression level, we would like to perform a microarray transcriptomic analysis. Keywords: treated vs untreated comparison 4 dye-swap - CATMA arrays
Project description:au08-06_mpk6_heat_stressed - au08-06_mpk6_heat_stressed - Mitogen Activated Protein Kinase (MAPK) signaling pathways are key regulators of cell proliferation, differentiation and stress effectors. The core of the MAP kinase signal transduction cascade is composed of a three-kinase module consisting of a MAP kinase kinase kinase (MAPKKK), a MAP kinase kinase (MAPKK), and a MAP kinase (MAPK). The signaling pathway is activated upon stimulation by a phosphorylation cascade. In previous studies, it was shown that the mpk6 KO mutant plants are significantly more tolerant to heat stress in comparison to wt and that after 3h treatment at 37°C, an activation of heat-shock proteins occures in the mpk6 mutant. To better understand the changes occuring in the mpk6 mutant upon heat stress at the gene expression level, we would like to perform a microarray transcriptomic analysis. - Mitogen Activated Protein Kinase (MAPK) signaling pathways are key regulators of cell proliferation, differentiation and stress effectors. The core of the MAP kinase signal transduction cascade is composed of a three-kinase module consisting of a MAP kinase kinase kinase (MAPKKK), a MAP kinase kinase (MAPKK), and a MAP kinase (MAPK). The signaling pathway is activated upon stimulation by a phosphorylation cascade. In previous studies, it was shown that the mpk6 KO mutant plants are significantly more tolerant to heat stress in comparison to wt and that after 3h treatment at 37°C, an activation of heat-shock proteins occures in the mpk6 mutant. To better understand the changes occuring in the mpk6 mutant upon heat stress at the gene expression level, we would like to perform a microarray transcriptomic analysis. Keywords: treated vs untreated comparison
Project description:Reactive oxygen species (ROS) have been characterized as both important signaling molecules and universal stressors that mediate many developmental and physiological responses. So far, details of the transcriptional mechanism of ROS-responsive genes are still largely unknown. In the study reported herein, we identified eight potential ROS-responsive cis-acting elements (ROSEs) from the promoters of genes upregulated by ROS. We also found that the APETALA2 (AP2/EREBP)-type transcription factor ERF6 could bind specifically to the ROSE7/GCC box. Co-expression of ERF6 enhanced luciferase activity driven by ROSE7. ERF6 interacted physically with mitogen-activated protein kinase 6 (MPK6), and also served as a substrate of MPK6. MPK6-mediated ERF6 phosphorylation at both Ser 266 and Ser 269 affected the dynamic alternation of ERF6 protein, which resulted in changes in ROS-responsive gene transcription. These data might provide new insight into the mechanisms that regulate ROS-responsive gene transcription via a complex of MPK6, ERF6, and the ROSE7/GCC box.
Project description:Ethylene gas is essential for many developmental processes and stress responses in plants. ETHYLENE INSENSITIVE2 (EIN2), an NRAMP-homologous integral membrane protein, plays an essential role in ethylene signaling but its function remains enigmatic. Here we report that phosphorylation-regulated proteolytic processing of EIN2 triggers its endoplasmic reticulum (ER)-nucleus translocation, which is essential for hormone signaling and response in Arabidopsis. Without ethylene, or in hormone receptors mutants, ER-tethered EIN2 shows CTR1 kinase-dependent phosphorylation. Ethylene exposure triggers dephosphorylation and proteolytic cleavage, resulting in rapid nuclear translocation of a carboxyl-terminal EIN2 fragment (C’). Plants containing mutations that mimic EIN2 dephosphorylation, or inactivate CTR1, show constitutive cleavage and nuclear localization of EIN2-C’, and EIN3/EIL1-dependent activation of ethylene responses. These findings uncover a mechanism of subcellular communication whereby ethylene gas stimulates rapid phosphorylation-dependent cleavage and nuclear movement of the EIN2-C’ peptide, thus linking hormone perception and signaling components located in the ER with nuclear-localized transcriptional regulators.
Project description:Reactive oxygen species (ROS) have been characterized as both important signaling molecules and universal stressors that mediate many developmental and physiological responses. So far, details of the transcriptional mechanism of ROS-responsive genes are still largely unknown. In the study reported herein, we identified eight potential ROS-responsive cis-acting elements (ROSEs) from the promoters of genes upregulated by ROS. We also found that the APETALA2 (AP2/EREBP)-type transcription factor ERF6 could bind specifically to the ROSE7/GCC box. Co-expression of ERF6 enhanced luciferase activity driven by ROSE7. ERF6 interacted physically with mitogen-activated protein kinase 6 (MPK6), and also served as a substrate of MPK6. MPK6-mediated ERF6 phosphorylation at both Ser 266 and Ser 269 affected the dynamic alternation of ERF6 protein, which resulted in changes in ROS-responsive gene transcription. These data might provide new insight into the mechanisms that regulate ROS-responsive gene transcription via a complex of MPK6, ERF6, and the ROSE7/GCC box. To identifiy the ERF6 regualted genes under ROS and HL treatment. Three-week old Col-0 and erf6-1 mutant plants before and after exposed to 2000 umol m-2s-1 illumination for 2 h were used for RNA extracted hybridization on Affymetrix microarrays.