Project description:Plant basic helix-loop-helix (bHLH) proteins play essential roles in physiological and developmental processes and are also involved in abiotic stresses. However, their exact roles in abiotic stress are still not fully understood, and most of them have not been functionally characterised. In the present study, we characterised the functional role of AtbHLH112 in response to abiotic stress. A WRKY gene, AtWRKY66, can regulate the expression of the AtbHLH112 via binding to W-box motifs present in its promoter. AtbHLH112 is a nuclear-localised protein, and its nuclear localisation is increased upon exposure to NaCl, mannitol and ABA. In addition to binding to the G-box motif, AtbHLH112 is found to bind to a novel motif M-bM-^@M-^\GGGCCGGTCM-bM-^@M-^] (named the GCG-box) to regulate gene expression. Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with tolerance to salt and drought. AtbHLH112 can confer stress tolerance via enhanced expression of POD and SOD genes to improve ROS scavenging ability and via upregulated expression of P5CS genes and decreased expression of P5CDH and PRODH genes to improve proline levels. Our data suggested that AtbHLH112 regulates the expression of genes via binding to the G-box and the GCG-box to improve stress-related pathways, such as ROS scavenging and proline biosynthesis. Differentially expression genes of AtbHLH112-overexpression plants and mutant (SALK_033618C) plants of Arabidopsis thaliana were measured under salt stressed and normal condition for 3 hours, respectively. Three independent experiments were performed at each treatment using different plants for each experiment.
Project description:Plant basic helix-loop-helix (bHLH) transcription factors are involved in physiological and developmental processes, and also play essential roles in abiotic stresses. However, their exact roles in abiotic stress are still need to be elucidated, and most of bHLHs have not been functionally characterized. In the present study, we characterized the functional role of AtbHLH112 in response to abiotic stresses. AtbHLH112 is a nuclear-localized protein, and its nuclear-localization is induced by salt, drought and ABA. Besides binding to E-box motif, AtbHLH112 is found to bind to a novel motif with the sequence M-bM-^@M-^\GG[GT]CC[GT][GA][TA]CM-bM-^@M-^] (GCG-box), and the binding affinity is induced by salt and ABA. Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with salt and drought tolerance. AtbHLH112 mediates stress tolerance by upregulating the expression of P5CS genes and decreasing the expression of P5CDH and PRODH genes to increase proline levels, and via enhancing the expression of POD and SOD genes to improve ROS scavenging ability. All data together suggested that AtbHLH112 regulates the expression of genes through binding to GCG-box and E-box to mediate the physiological stress responses, including proline biosynthesis and ROS scavenging pathways to enhance stress tolerance. Differentially expression genes of AtbHLH112-overexpression plants, mutant (SALK_033618C) plants and wild type of Columbia Arabidopsis thaliana were measured under salt stressed and normal condition for 3 hours, respectively. Three independent experiments were performed at each treatment using different plants for each experiment.
Project description:Plant basic helix-loop-helix (bHLH) proteins play essential roles in physiological and developmental processes and are also involved in abiotic stresses. However, their exact roles in abiotic stress are still not fully understood, and most of them have not been functionally characterised. In the present study, we characterised the functional role of AtbHLH112 in response to abiotic stress. A WRKY gene, AtWRKY66, can regulate the expression of the AtbHLH112 via binding to W-box motifs present in its promoter. AtbHLH112 is a nuclear-localised protein, and its nuclear localisation is increased upon exposure to NaCl, mannitol and ABA. In addition to binding to the G-box motif, AtbHLH112 is found to bind to a novel motif “GGGCCGGTC” (named the GCG-box) to regulate gene expression. Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with tolerance to salt and drought. AtbHLH112 can confer stress tolerance via enhanced expression of POD and SOD genes to improve ROS scavenging ability and via upregulated expression of P5CS genes and decreased expression of P5CDH and PRODH genes to improve proline levels. Our data suggested that AtbHLH112 regulates the expression of genes via binding to the G-box and the GCG-box to improve stress-related pathways, such as ROS scavenging and proline biosynthesis.
Project description:Plant basic helix-loop-helix (bHLH) transcription factors are involved in physiological and developmental processes, and also play essential roles in abiotic stresses. However, their exact roles in abiotic stress are still need to be elucidated, and most of bHLHs have not been functionally characterized. In the present study, we characterized the functional role of AtbHLH112 in response to abiotic stresses. AtbHLH112 is a nuclear-localized protein, and its nuclear-localization is induced by salt, drought and ABA. Besides binding to E-box motif, AtbHLH112 is found to bind to a novel motif with the sequence “GG[GT]CC[GT][GA][TA]C” (GCG-box), and the binding affinity is induced by salt and ABA. Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with salt and drought tolerance. AtbHLH112 mediates stress tolerance by upregulating the expression of P5CS genes and decreasing the expression of P5CDH and PRODH genes to increase proline levels, and via enhancing the expression of POD and SOD genes to improve ROS scavenging ability. All data together suggested that AtbHLH112 regulates the expression of genes through binding to GCG-box and E-box to mediate the physiological stress responses, including proline biosynthesis and ROS scavenging pathways to enhance stress tolerance.
Project description:Redox Responsive Transcription Factor1 (RRTF1) in Arabidopsis is rapidly and transiently upregulated by H202, as well as biotic and abiotic induced redox signals. Inactivation of RRTF1 restricts and overexpression promotes reactive oxygen species (ROS) accumulation in response to stress. Overexpressor (oe) lines are impaired in root and shoot development, light sensitive and susceptible to Alternaria brassicae infection. These symptoms are diminished by the beneficial root endophyte Piriformospora indica which reduces ROS accumulation locally in roots and systemically in shoots, and by antioxidants and ROS inhibitors which scavenge ROS. More than 850 stress-, redox-, ROS regulated-, ROS scavenging-, defense-, cell death- and senescence-related genes are regulated by RRTF1, ~ 30% of them have ROS related functions. Bioinformatic analyses and in vitro DNA binding assays demonstrate that RRTF1 binds to GCC-box and GCC-box like sequences in the promoter of RRTF1-responsive genes. Upregulation of RRTF1 by stress stimuli as well as H2O2 requires WRKY18/40/60. RRTF1 is co-regulated with the phylogenetically related RAP2.6, which contains GCC-box like sequene in its promoter, but RAP2.6 oe lines do not accumulate higher ROS levels. RRTF1 stimulates systemic ROS accumulation in distal non-stressed leaves. We conclude that the highly conserved RRTF1 rapidly, transiently and systemically induce ROS accumulation in response to ROS and ROS-producing abiotic and biotic stress signals. Necrotrophs stimulate RRTF1 expression, while symbiotic interactions of Arabidopsis with (hemi)-biotrophs and P. indica do not affect or repress RRTF1 expression. Mature leaves of 5 weeks-old Col-0 wild type and RRTF1-overexpressor Arabidopsis (called oe18), which were grown on soil under short-day condition at 20˚C, were subjected to RNA extraction and Affymetrix microarray analysis. Three biological independent experiments for both Col-0 and oe18 were performed.
Project description:Redox Responsive Transcription Factor1 (RRTF1) in Arabidopsis is rapidly and transiently upregulated by H202, as well as biotic and abiotic induced redox signals. Inactivation of RRTF1 restricts and overexpression promotes reactive oxygen species (ROS) accumulation in response to stress. Overexpressor (oe) lines are impaired in root and shoot development, light sensitive and susceptible to Alternaria brassicae infection. These symptoms are diminished by the beneficial root endophyte Piriformospora indica which reduces ROS accumulation locally in roots and systemically in shoots, and by antioxidants and ROS inhibitors which scavenge ROS. More than 850 stress-, redox-, ROS regulated-, ROS scavenging-, defense-, cell death- and senescence-related genes are regulated by RRTF1, ~ 30% of them have ROS related functions. Bioinformatic analyses and in vitro DNA binding assays demonstrate that RRTF1 binds to GCC-box and GCC-box like sequences in the promoter of RRTF1-responsive genes. Upregulation of RRTF1 by stress stimuli as well as H2O2 requires WRKY18/40/60. RRTF1 is co-regulated with the phylogenetically related RAP2.6, which contains GCC-box like sequene in its promoter, but RAP2.6 oe lines do not accumulate higher ROS levels. RRTF1 stimulates systemic ROS accumulation in distal non-stressed leaves. We conclude that the highly conserved RRTF1 rapidly, transiently and systemically induce ROS accumulation in response to ROS and ROS-producing abiotic and biotic stress signals. Necrotrophs stimulate RRTF1 expression, while symbiotic interactions of Arabidopsis with (hemi)-biotrophs and P. indica do not affect or repress RRTF1 expression.
Project description:Redox Responsive Transcription Factor1 (RRTF1) in Arabidopsis is rapidly and transiently upregulated by H202, as well as biotic and abiotic induced redox signals. Inactivation of RRTF1 restricts and overexpression promotes reactive oxygen species (ROS) accumulation in response to stress. Overexpressor (oe) lines are impaired in root and shoot development, light sensitive and susceptible to Alternaria brassicae infection. These symptoms are diminished by the beneficial root endophyte Piriformospora indica which reduces ROS accumulation locally in roots and systemically in shoots, and by antioxidants and ROS inhibitors which scavenge ROS. More than 850 stress-, redox-, ROS regulated-, ROS scavenging-, defense-, cell death- and senescence-related genes are regulated by RRTF1, ~ 30% of them have ROS related functions. Bioinformatic analyses and in vitro DNA binding assays demonstrate that RRTF1 binds to GCC-box and GCC-box like sequences in the promoter of RRTF1-responsive genes. Upregulation of RRTF1 by stress stimuli as well as H2O2 requires WRKY18/40/60. RRTF1 is co-regulated with the phylogenetically related RAP2.6, which contains GCC-box like sequene in its promoter, but RAP2.6 oe lines do not accumulate higher ROS levels. RRTF1 stimulates systemic ROS accumulation in distal non-stressed leaves. We conclude that the highly conserved RRTF1 rapidly, transiently and systemically induce ROS accumulation in response to ROS and ROS-producing abiotic and biotic stress signals. Necrotrophs stimulate RRTF1 expression, while symbiotic interactions of Arabidopsis with (hemi)-biotrophs and P. indica do not affect or repress RRTF1 expression.
Project description:Redox Responsive Transcription Factor1 (RRTF1) in Arabidopsis is rapidly and transiently upregulated by H202, as well as biotic and abiotic induced redox signals. Inactivation of RRTF1 restricts and overexpression promotes reactive oxygen species (ROS) accumulation in response to stress. Overexpressor (oe) lines are impaired in root and shoot development, light sensitive and susceptible to Alternaria brassicae infection. These symptoms are diminished by the beneficial root endophyte Piriformospora indica which reduces ROS accumulation locally in roots and systemically in shoots, and by antioxidants and ROS inhibitors which scavenge ROS. More than 850 stress-, redox-, ROS regulated-, ROS scavenging-, defense-, cell death- and senescence-related genes are regulated by RRTF1, ~ 30% of them have ROS related functions. Bioinformatic analyses and in vitro DNA binding assays demonstrate that RRTF1 binds to GCC-box and GCC-box like sequences in the promoter of RRTF1-responsive genes. Upregulation of RRTF1 by stress stimuli as well as H2O2 requires WRKY18/40/60. RRTF1 is co-regulated with the phylogenetically related RAP2.6, which contains GCC-box like sequene in its promoter, but RAP2.6 oe lines do not accumulate higher ROS levels. RRTF1 stimulates systemic ROS accumulation in distal non-stressed leaves. We conclude that the highly conserved RRTF1 rapidly, transiently and systemically induce ROS accumulation in response to ROS and ROS-producing abiotic and biotic stress signals. Necrotrophs stimulate RRTF1 expression, while symbiotic interactions of Arabidopsis with (hemi)-biotrophs and P. indica do not affect or repress RRTF1 expression. The seedlings were grown on MS medium with 1.37% sucrose under short day conditions and low light intensity (30 µmol m-2s-1) at 20˚C for 14 days. Transcriptome analysis was performed for the rrtf1 knock-out line and a RRTF1-overlexpressor line (called oe18) in comparison to wild-type seedlings.
Project description:In the current report, we report that ThbZIP1 is a direct target gene of the ThABF1 transcription factor. There are three ABRE motifs in the promoter of ThbZIP1, Yeast one-hybrid (Y1H) assays showed that a ABF protein, ThABF1, specifically binds to the ABRE motifs. The interaction between ThABF1 and the promoter of ThbZIP1 was further confirmed by transient expression assays in tobacco leaves. Chromatin Immunoprecipitation (ChIP) results suggested that binding of ThABF1 to ABRE motifs in the promoter of ThbZIP1 occurs in vivo in Tamarix hispida to regulate the expression of ThbZIP1. Moreover, ThABF1 and ThbZIP1 share similar expression patterns in response to salt, drought, ABA, methyl viologen (MV) and cold stress. Microarray analyses results showed there were 1,662 and 1,609 genes that were significantly upregulated or downregulated, respectively, under ABA stress conditions. ThbZIP1 regulated the genes via binding to the C-, G- or A-box motifs in their promoter sequences. Based on these data, the results suggested a regulatory network model mediated by ThbZIP1, under abiotic stress conditions, ThABF1 regulates the expression of ThbZIP1, and the activated ThbZIP1 binds to bZIP recognition sequences or other motifs to regulate the expression of genes containing these motifs in their promoters. Differentially expression genes of ThbZIP1-overexpression plants and wild type of Columbia Arabidopsis thaliana were measured under ABA stressed and normal condition for 3 hours, respectively. Two independent experiments were performed at each treatment using different plants for each experiment.