Project description:The role of ANAC017 in leaf senescence was assessed by covering leaf 6-7 of 5 week old plants. Samples of Col-0, anac017 knock-out and two ANAC017 overexpression lines were compared of day 0, 1 and 3 of the timecourse. ANAC017 OE lines show accelerated senescence during this time.
Project description:Lincomycin (LIN)-mediated inhibition of protein synthesis in chloroplasts prevents greening of seedlings, represses the activity of photosynthesis-related genes in the nucleus including LHCB1.2, and induces the phenylpropanoid pathway, resulting in production of anthocyanins. In genomes uncoupled (gun) mutants, LHCB1.2 expression is maintained in the presence of LIN or other inhibitors of early chloroplast development. In a screen using concentrations of LIN lower than those employed to isolate gun mutants, we have identified happy on lincomycin (holi) mutants. Several holi mutants show increased tolerance to LIN, exhibiting de-repressed LHCB1.2 expression and chlorophyll synthesis in seedlings. The mutations responsible were identified by whole-genome SNP mapping, and most were found to affect the phenylpropanoid pathway. However, LHCB1.2 expression appears not to be directly regulated by phenylpropanoids, as indicated by metabolic profiling of mutants. The most potent holi mutant is defective in a subunit of cellulose synthase encoded by IRREGULAR XYLEM3, and comparative analysis of this and other cell-wall mutants establishes a link between secondary cell-wall integrity and tolerance to LIN, possibly involving altered ABA metabolism or sensing.
2022-04-05 | GSE130337 | GEO
Project description:Overexpression of PdeGATA3 results in a dwarf phenotype
Project description:Stresses that target mitochondrial function lead to altered transcriptional responses for 100-1000s of genes genome wide, and are signalled via retrograde communication pathways within the cell. rao2 mutants contain a mutation in the NAC family transcription factor ANAC017 and cannot induce stress responsive genes (such as the mitochondrial alternative oxidase 1a) in response to mitochondrial dysfunction. We sought to define the global gene network regulated through RAO2 function in response to mitochondrial stress (mimicked through treatment of plants with antimycin A - a specific inhibitor of complex III in the mitochondrial electron transfer chain), and non-specific stress signals such as hydrogen peroxide. We have defined global stress responses that are positively and negatively mediated by RAO2 function, and show that greater than 80% of transcripts that are differentially regulated under H2O2 stress require proper functioning of ANAC017 for a normal stress responses. We used Affymetrix microarray to characterise global gene expression profiles for mutant plants with compromised mitochondrial retrograde signalling (rao2 mutants), to define the genome wide transcriptional network regulated through RAO1 function under mitochondrial stress and hydrogen peroxide stress. rao2 EMS lines, independent T-DNA knock-out lines for ANAC017 (anac017-1), ANAC017 gain of function mutants (anac017-2) and wild type seedlings were grown for 14 days, the optimal stage as defined by forward genetic screens that identifed rao2 mutants. Seedlings were grown on GamborgB5 plates and treated by spraying plants with 50 µM antimycin A (an elicitor of mitochondrial retrograde signalling) or 20mM hydrogen peroxide while mock control samples were sprayed with deionised water. Samples were collected after 3hr of treatment for global expression profiling.
Project description:Lincomycin is a lincosamide antibiotic that forms cross-links within the peptidyl transferase loop region of the 23S rRNA of the 50S subunit of the bacterial ribosome, thereby inhibiting protein synthesis. We have previously reported that lincomycin at concentrations below the minimum inhibitory concentration potentiates the production of secondary metabolites in actinomycete strains. We aimed to elucidate the fundamental mechanisms underlying lincomycin induction of secondary metabolism in actinomycetes. Therefore, the dose-dependent response of lincomycin on gene expression of the model actinomycetes Streptomyces coelicolor A3(2) and possible relationships to secondary metabolism have been investigated.
Project description:To identify putative regulatory elements enriched in the promoters of target genes of the PGE-dependent retrograde signaling pathway, we analyzed 500 bp regions of sequence upstream of genes whose expression was down-regulated by lincomycin. We treated dark-grown Arabidopsis seedlings with lincomycin, sampled them before or after a short illumination and examined the genomic response using Affymetrix ATH1 oligonucleotide microarrays. Differentially regulated genes were ranked based on descending degree of significance (p-value) and the top 50 genes affected by lincomycin in dark grown seedlings and top 50 genes affected by the antibiotic after illumination were selected for further analysis. Keywords: does response
Project description:Mitochondria are crucial for plant viability and are able to communicate information on their functional status to the cellular nucleus via retrograde signalling, thereby affecting gene expression. It is currently unclear if retrograde signalling in response to constitutive mitochondrial biogenesis defects is mediated by the same pathways as those triggered during acute mitochondrial dysfunction. Furthermore, it is unknown if retrograde signalling can effectively improve plant performance when mitochondrial function is constitutively impaired. Here we show that retrograde signalling in mutants defective in mitochondrial proteins RNA polymerase rpotmp or prohibitin atphb3 can be suppressed by knocking out the transcription factor ANAC017. Genome-wide RNA-seq expression analysis revealed that ANAC017 is almost solely responsible for the most dramatic transcriptional changes common to rpotmp and atphb3 mutants, regulating both classical marker genes such as alternative oxidase 1a (AOX1a) and also previously-uncharacterised DUF295 genes that appear to be new retrograde markers. In contrast, ANAC017 does not regulate intra-mitochondrial gene expression or transcriptional changes unique to either rpotmp or atphb3 genotype, suggesting the existence of currently unknown signalling cascades. The data show that the role of ANAC017 extends beyond common retrograde transcriptional responses and affects downstream protein abundance and enzyme activity of alternative oxidase, as well as steady state energy metabolism in atphb3 plants. Furthermore, detailed growth analysis revealed that ANAC017-dependent retrograde signalling provides benefits for growth and productivity in plants with mitochondrial defects. In conclusion, ANAC017 plays a key role in both biogenic and operational mitochondrial retrograde signalling, and improves plant performance when mitochondrial function is constitutively impaired.
Project description:To identify putative regulatory elements enriched in the promoters of target genes of the PGE-dependent retrograde signaling pathway, we analyzed 500 bp regions of sequence upstream of genes whose expression was down-regulated by lincomycin. We treated dark-grown Arabidopsis seedlings with lincomycin, sampled them before or after a short illumination and examined the genomic response using Affymetrix ATH1 oligonucleotide microarrays. Differentially regulated genes were ranked based on descending degree of significance (p-value) and the top 50 genes affected by lincomycin in dark grown seedlings and top 50 genes affected by the antibiotic after illumination were selected for further analysis. Experiment Overall Design: 2*2 factorial design, two variables are (1) with/without lincomycin treatment (2) with/without red illumination. There are 2 replicates for each condition.
Project description:Stresses that target mitochondrial function lead to altered transcriptional responses for 100-1000s of genes genome wide, and are signalled via retrograde communication pathways within the cell. rao2 mutants contain a mutation in the NAC family transcription factor ANAC017 and cannot induce stress responsive genes (such as the mitochondrial alternative oxidase 1a) in response to mitochondrial dysfunction. We sought to define the global gene network regulated through RAO2 function in response to mitochondrial stress (mimicked through treatment of plants with antimycin A - a specific inhibitor of complex III in the mitochondrial electron transfer chain), and non-specific stress signals such as hydrogen peroxide. We have defined global stress responses that are positively and negatively mediated by RAO2 function, and show that greater than 80% of transcripts that are differentially regulated under H2O2 stress require proper functioning of ANAC017 for a normal stress responses. We used Affymetrix microarray to characterise global gene expression profiles for mutant plants with compromised mitochondrial retrograde signalling (rao2 mutants), to define the genome wide transcriptional network regulated through RAO1 function under mitochondrial stress and hydrogen peroxide stress.