Project description:In plants, transposons and non-protein-coding repeats are epigenetically silenced by CG and non-CG methylation. This pattern of methylation is mediated in part by small RNAs and two specialized RNA polymerases, Pol IV and Pol V, in a process called RNA-directed DNA methylation. By contrast, many protein-coding genes transcribed by Pol II contain in their gene bodies exclusively CG methylation that is independent of small RNAs and Pol IV/Pol V activities. It is unclear how the different methylation machineries distinguish between transposons and genes. Here we report on a group of atypical genes that display in their coding region a transposon-like methylation pattern, which is associated with gene silencing in sporophytic tissues. We performed a methylation-sensitive amplification polymorphism analysis to search for targets of RNA-directed DNA methylation in Arabidopsis thaliana and identified several members of a gene family encoding cysteine-rich peptides (CRPs). We also examined small RNA abundance at individual CRP genes in the wild type plant, nrpd1, and rdr2 mutant plants.
Project description:Many eukaryotic RNAs have been considered non-coding as they only contain short open reading frames (sORFs). There is increasing evidence for the translation of these sORFs into bioactive peptides. Yet only a few small peptides are annotated in the model organism Arabidopsis thaliana. To aid the functional annotation of small peptides, we have developed ARA-PEPs, a repository and webserver of putative peptides encoded by sORFs in the Arabidopsis genome from in house Tiling arrays, RNA sequencing and from publicly available datasets. In order to identify novel oxidative stress-induced peptides in Arabidopsis thaliana a tiling array analysis (GeneChip® Arabidopsis Tiling 1.0R Arrays ) was performed on mRNA extracted from leaves inoculated with Botrytis cinerea (BC). Normalized log signals were obtained using the Affymetrix Tiling Analysis Software - Version 1.1, Build 2. ON and OFF probes were selected using a threshold, based on positive controls. Next, groups of 4-13 successive ON probes were combined into short TARs and a selection was made of TARs having an average signal intensity at least 2.6-fold higher after BC treatment compared to the control treatment, resulting in 195 BC induced TARs.
Project description:We present a functional characterisation of two members of the IDA-LIKE (IDL) peptide family in Arabidopsis thaliana, IDL6 and IDL7. They are processed both C- and N-terminally to produce active peptides. Structure analyses of synthesized IDL6 and IDL7 peptides indicate that they lack secondary structure elements. Localisation studies suggest that the peptides require a signal peptide and C-terminally processing to be correctly transported out of the cell. Treatment of plants with synthetic IDL6 and IDL7 peptides resulted in down-regulation of a broad range of stress-responsive genes, including early stress-responsive transcripts, dominated by a large group of ZINC FINGER PROTEINS (ZFPs), WRKYs and genes encoding calcium-dependent proteins. idl6 and idl7 mutants were more tolerant to salt, whereas the respective overexpression lines displayed increased sensitivity to both salt and oxidative stress. Taken together, our results suggest that the putative peptide ligands IDL6 and IDL7 act as suppressors of abiotic stress responses in Arabidopsis.
Project description:Transcriptional profiling of Arabidopsis thaliana 12-days old seedlings comparing Col-0 wild type with transgenic plants with altered expression of dual-targetting plastid/mitochondrial organellar RNA-polymerase RPOTmp. Transgenic plants used for experiment were: overexpressor plants obtained by transformation of Col-0 WT plants with genetic constructs created in [Tarasenko et al., 2016] contained catalytic part of RPOTmp enzyme with transit peptides of RPOTm (mitochondrial) and RPOTp (plastid) by agrobacterial transformation; plants with complementation of RPOTmp functions in mitochondria or chloroplasts obtained from transformation of GABI_286E07 rpotmp knockout-mutant plants with genetic constructs created in [Tarasenko et al., 2016]. Goal was to determine the effects of RPOTmp knockout/overexpression on global Arabidopsis thaliana gene expression.
Project description:The objective of the study is to profile histone H3 lysine nine di-methylation (H3K9me2) in Arabidopsis thaliana and to correlate it with DNA methylation.
Project description:Arabidopsis thaliana is a well-established model system for the analysis of the basic physiological and metabolic pathways of plants. The presented model is a new semi-quantitative mathematical model of the metabolism of Arabidopsis thaliana. The Petri net formalism was used to express the complex reaction system in a mathematically unique manner. To verify the model for correctness and consistency concepts of network decomposition and network reduction such as transition invariants, common transition pairs, and invariant transition pairs were applied. Based on recent knowledge from literature, including the Calvin cycle, glycolysis and citric acid cycle, glyoxylate cycle, urea cycle, sucrose synthesis, and the starch metabolism, the core metabolism of Arabidopsis thaliana was formulated. Each reaction (transition) is experimentally proven. The complete Petri net model consists of 134 metabolites, represented by places, and 243 reactions, represented by transitions. Places and transitions are connected via 572 edges.