Project description:The goal of the project is to determine proteomic changes occuring in Arabidopsis thalina plants overexpressing Phospholipid:diacylglycerol acyltransferase 1 (PDAT1) gene. This modification resulted in prolongation of plant lifespan together with profound increase of cold and hot tolerance, asdescribed in Demski et.al, 2020. In this study we have compared Arabidopsis leaf proteomes of wild-type plandt and two independently created overexpressor strains grown in normal conditions.
Project description:Keeping imbibed seeds at low temperatures for a certain period, so called seed vernalization (SV) treatment, promotes seed germination and subsequent flowering in various plants. Vernalization-promoting flowering requires GSH. However, the expression patterns analyzed by GeneChip arrays showed that increased GSH biosynthesis partially mimics SV treatment in Arabidopsis thaliana. SV treatment (keeping imbibed seeds at 4°C for 24 h) induced a specific pattern of gene expression and promoted subsequent flowering in wild-type plants. A similar pattern was observed at 22°C in transgenic plants (35S-GSH1 plants) overexpressing the γ-glutamylcysteine synthetase gene GSH1, coding an enzyme limiting GSH biosynthesis, under the control of the cauliflower mosaic virus 35S promoter. This pattern was strengthened at 4°C but flowering was less responsive to SV treatment. There was a difference in the transcript behaviour of the flowering repressor FLC between wild-type and 35S-GSH1 plants. Unlike other genes responsive to SV treatment, SV-dependent decrease in FLC in wild-type plants was reversed in 35S-GSH1 plants. SV treatment increased GSSG level in wild-type seeds, whereas GSSG level was high in 35S-GSH1 plants, even at a non-vernalizing temperature. Taking into consideration that low temperatures stimulate GSH biosynthesis and bring about oxidative stress, GSSG is considered to trigger low temperature response, but enhanced GSH synthesis was not enough for mimicking SV treatment. To complete it, it essentially required the cellular redox retransition from the oxidized to the reduced state that is observed after the seed vernalization treatment.
Project description:We investigated the relationships of the two immune-regulatory plant metabolites salicylic acid (SA) and pipecolic acid (Pip) in the establishment of plant systemic acquired resistance (SAR) in Arabidopsis thaliana induced by the bacterial pathogen Pseudomonas syringae. To characterize the transcriptional SAR response, we used wild-type Col-0 plants, SA-deficient sid2 plants and Pip-deficient ald1 plants and performed RNA-sequencing analyses (Bernsdorff et al., Plant Cell, 2016). SAR establishment in the wild-type is characterized by a strong transcriptional response systemically induced in the foliage that prepares plants for future pathogen attack by pre-activating multiple stages of defense signaling. Whereas systemic Pip elevations are indispensable for SAR and necessary for virtually the whole transcriptional SAR response, a moderate but significant SA-independent component of SAR activation and SAR gene expression is revealed. Arabidopsis thaliana plants were grown individually in pots containing a mixture of soil, vermiculite and sand (8:1:1) in a controlled cultivation chamber with a 10-h day (9 AM to 7 PM; photon flux density 100 mol m-2 s-1) / 14-h night cycle and a relative humidity of 70 %. Day and night temperatures were set to 21C and 18C, respectively. Experiments were performed with 5- to 6-week-old, naive plants exhibiting a uniform appearance. To activate SAR, plants were infiltrated between 10 AM and 12 AM into three lower (1) leaves with suspensions of the bacterial pathogen Pseudomonas syringae pv. maculicola (OD600 = 0.005). Infiltration with 10 mM MgCl2 served as the mock-control treatment. Upper (2) leaves were harvested 48 h after the primary treatment for the determination of systemic gene expression by RNA-seq analyses. Three biologically independent, replicate SAR induction experiments were performed with Col-0 and sid2 plants (experimental set 1), and three other biologically independent experiments with Col-0 and ald1 plants (experimental set 2). In each SAR experiment, at least 6 upper (2) leaves from 6 different plants pre-treated in 1 leaves with Psm (MgCl2) were pooled for one biological Psm- (mock-control) replicate. In this way, 3 biologically independent, replicate samples per treatment and plant genotype were obtained within each SAR set.
Project description:Comparison of gene expression changes in safener- or BF-treated wild type (Col0) or mutants (tga2tga3tga5tga6, sid2-2) of the salicylic acid signaling pathway. Measurements of three biological samples were prepared for each genotype.