Project description:Micro RNAs (miRNAs) are a class of small endogenous RNAs conserved in eukaryotic organisms including plants. They suppress gene expression post-transcriptionally in many different biological processes. Previously, we reported salinity-induced changes in gene expression in transgenic Arabidopsis thaliana plants that constitutively expressed a pea abscisic acid-responsive (ABR17) gene. In the current study, we used a microarray to investigate the role of miRNA-mediated post-transcriptional gene regulation in these same transgenic plants in the presence and absence of salinity stress. We identified nine miRNAs that were significantly modulated due to ABR17 gene expression, and seven miRNAs that were modulated in response to salt stress. The target genes regulated by these miRNAs were identified using starBase (sRNA target Base) Degradome analysis and through 5' RNA Ligase Mediated-Rapid Amplification of cDNA Ends (RLM-RACE). Our findings revealed miRNA:mRNA interactions comprising regulatory networks of Auxin Response Factor (ARF), ARGONAUTE 1, (AGO1), Dicer-like proteins 1 (DCL1), Squamosa Promoter Binding (SPB), NAC, APETALA 2 (AP2), Nuclear Factor-Y (NFY), RNA binding proteins, Arabidopsis thaliana vacuolar phyrophosphate 1 (AVP1) and Pentatricopetide repeat (PPR) in ABR17 transgenic A. thaliana, which control physiological, biochemical and stress signalling cascades due to the imposition of salt stress. Our results are discussed within the context of the effect of the transgene, ABR17, and the roles miRNA expression may play in mediating plant responses to salinity.
Project description:Micro RNAs (miRNAs) are a class of small endogenous RNAs conserved in eukaryotic organisms including plants. They suppress gene expression post-transcriptionally in many different biological processes. Previously, we reported salinity-induced changes in gene expression in transgenic Arabidopsis thaliana plants that constitutively expressed a pea abscisic acid-responsive (ABR17) gene. In the current study, we used a microarray to investigate the role of miRNA-mediated post-transcriptional gene regulation in these same transgenic plants in the presence and absence of salinity stress. We identified nine miRNAs that were significantly modulated due to ABR17 gene expression, and seven miRNAs that were modulated in response to salt stress. The target genes regulated by these miRNAs were identified using starBase (sRNA target Base) Degradome analysis and through 5' RNA Ligase Mediated-Rapid Amplification of cDNA Ends (RLM-RACE). Our findings revealed miRNA:mRNA interactions comprising regulatory networks of Auxin Response Factor (ARF), ARGONAUTE 1, (AGO1), Dicer-like proteins 1 (DCL1), Squamosa Promoter Binding (SPB), NAC, APETALA 2 (AP2), Nuclear Factor-Y (NFY), RNA binding proteins, Arabidopsis thaliana vacuolar phyrophosphate 1 (AVP1) and Pentatricopetide repeat (PPR) in ABR17 transgenic A. thaliana, which control physiological, biochemical and stress signalling cascades due to the imposition of salt stress. Our results are discussed within the context of the effect of the transgene, ABR17, and the roles miRNA expression may play in mediating plant responses to salinity. In this miRNA-microarray experiment, a total of 4 samples were analyzed with their 3 biological replicates. Two samples, WT and ABR17 control (without salt treatment), were used as reference controls.
Project description:Expression of the F-Box protein Leaf Curling Responsiveness (LCR) is regulated by microRNA, miR394, and alterations to this interplay in Arabidopsis thaliana produce defects in leaf polarity and shoot apical meristem (SAM) organisation. Although the miR394-LCR node has been documented in Arabidopsis, the identification of proteins targeted by LCR F-box itself has proven problematic. Here, a proteomic analysis of shoot apices from plants with altered LCR levels identified a member of the Major Latex Protein (MLP) family gene as a potential LCR F-box target. Bioinformatic and molecular analyses also suggested that other MLP family members are likely to be targets for this post-translational regulation. Direct interaction between LCR F-Box and MLP423 was validated. Additional MLP members had reduction in protein accumulation, in varying degrees, mediated by LCR F-Box. Transgenic Arabidopsis lines, in which MLP28 expression was reduced through an artificial miRNA technology, displayed severe developmental defects, including changes in leaf patterning and morphology, shoot apex defects, and eventual premature death. These phenotypic characteristics resemble those of Arabidopsis plants modified to over-express LCR. Taken together, the results demonstrate that MLPs are driven to degradation by LCR, and indicate that MLP gene family is target of miR394-LCR regulatory node, representing potential targets for directly post-translational regulation mediated by LCR F-Box. In addition, MLP28 family member is associated with the LCR regulation that is critical for normal Arabidopsis development.
Project description:CuZn-superoxide dismutase (CuZn-SOD) and ascorbate peroxidase (APX) constitute first line of defence against oxidative stress. In the present study, PaSOD and RaAPX genes from Potentilla atrosanguinea and Rheum australe, respectively were overexpressed individually as well as in combination in Arabidopsis thaliana. We performed RNA-seq analysis of wild type and transgenic Arabidopsis thaliana overexpressing CuZn-SOD, APX and CuZn-SOD + APX under control and salt stress
Project description:The overall objective was to document transcriptomic changes in the guard cells of Arabidopsis thaliana under short (1x) - and long-term (3x) saline growth conditions. Guard cells of Arabidopsis responded also to the intensity of the salt management by the microarray datasets clearly clustering in (-) salt, 1x salt and 3x salt. Similarly, more GO terms were significantly enriched in differentially expressed guard cell genes of 1 x salt than 3x salt treated plants.
Project description:The goal of this project is to compare the primary metabolite profile in different tissue types of the model plant Arabidopsis thaliana. Specifically, plants were grown hydroponically under the long-day (16hr light/day) condition at 21C. Tissue samples, including leaves, inflorescences, and roots were harvest 4 1/2 weeks post sowing. Untargeted primary metabolites profiling was carried out using GCTOF.
Project description:Arabidopsis thaliana is a glycophyte with a low salt tolerance, while Eutrema is a halophyte with a very high salt tolerance. To elucidate the transcriptional basis of this difference, we performed hydroponis culture experiments where we grew plants under control conditions (25 mM NaCl) or under salt stress (200 mM NaCl for both species, 500 mM for Eutrema). Salt concentration was increased for the stress treatments by increments of 50 mM per day (25 mM on the first day). Plants were grown at the final NaCl concentration for an additional week, when rosettes were harvested for RNA isolation.Expression patterns were compared between treatments and between species.
Project description:Lysine 2-hydroxyisobutyrylation (Khib) is one of the newly discovered post-translational modifications (PTMs) through protein acylation. It has been reported to be widely distribute in both eukaryotes and prokaryotes, and plays an important role in chromatin conformation change, gene transcription, subcellular localization, protein-protein interaction, signal transduction, and cellular proliferation. In this study, we compared the siliques from Arabidopsis thaliana under salt stress (Ss) with those in the control (Cs). The results showed that this highly conserved modification was abundant in siliques. However, there were certain significant differences between the Ss and the Cs: 3810 normalized 2-hydroxyisobutyrylation sites on 1254 proteins were identified in siliques under salt stress, and lysine 2-hydroxyisobutyrylation was up-regulated at 96 sites on 78 proteins while down-regulated at 282 sites on 205 proteins in Ss. In the KEGG pathway enrichment analysis, Khib-modified proteins were enriched in several pathways related to energy metabolism, including gluconeogenesis pathway, pentose phosphate pathway, and pyruvate metabolism. Overall, our work reveals the first systematic analysis of Khib proteome in Arabidopsis siliques under salt stress, and sheds a light on the future studies on the regulatory mechanisms of Khib during the salt stress response of plants.
Project description:Like protein coding genes, loci that produce microRNAs (miRNAs) are generally considered to be under purifying selection, consistent with miRNA polymorphisms being able to cause disease. Nevertheless, it has been hypothesized that variation in miRNA genes may contribute to phenotypic diversity. Here we demonstrate that a naturally occurring polymorphism in the MIR164A gene interacts epistatically with an unlinked locus to affect leaf shape and shoot architecture in Arabidopsis thaliana. A single-base pair substitution in the miRNA complementary sequence alters the stability of the miRNA:miRNA* duplex. It thereby interferes with processing of the precursor and greatly reduces miRNA accumulation. We demonstrate that this is not a rare exception, but that natural strains of Arabidopsis thaliana harbor dozens of similar polymorphisms that affect processing of a wide range of miRNA precursors. Our results suggest that natural variation in miRNA processability due to cis mutations is a common contributor to phenotypic variation in plants. sRNA sequencing transgenic A. thaliana