Project description:We studied the changes that occur in gene transcription during seasonal senescence in Populus trichocarpa pioneer leaves and fine roots. Plant senescence is a strictly regulated physiological process that allows relocating of valuable nutrients from senescent tissues before death. It might be induced by internal or external factors and among them, phytohormones play an undoubtedly significant role. Senescence was extensively studied in leaves, but the aging of other ephemeral organs, located underground, and its drivers are still poorly understood. We focused on collective results to fill in the knowledge gap about senescence of fine, absorptive roots and leaves in order to check if there are universal mechanisms involved during plant organ senescence. Transcriptional profiling was conducted with the use of microarrays to identify genes involved in developmental PCD. Samples were collected three times during a growth season. The first collection was considered as a control and was collected in early summer (July 7–15) when leaves and the root system were fully developed and functional. The second group of leaf and root samples were harvested in early autumn (October 1–7) when chlorophyll levels in leaves had decreased by approximately 40% and when fine roots had changed in color from white to brown. The third group of samples were harvested in the middle of autumn (November 2–9) when chlorophyll levels in leaves decreased by approximately 65% and fine roots were dark brown or black color. Our results reveal the important role of phytohormones in regulating the senescence of both studied organs. The transcriptomic analyses showed significant changes in gene expression that are associated with phytohormones, especially with ABA and jasmonates. We conclude that phytohormonal regulation of senescence in roots and leaves is organ-specific. In roots, phytohormones are involved indirectly in regulation of senescence by increasing tolerance for cold or resistance for pathogens, whereas such correlation was not observed in leaves.
Project description:We studied the changes that occur in gene transcription and the biosynthesis of cell-wall-related compounds during xylogenesis in Populus trichocarpa pioneer roots and stems. Transcriptional profiling was conducted with the use of microarrays to identify genes involved in xylem formation. Pioneer roots were examined in segments corresponding to their developmental stage: apical meristem (PR1), primary development (PR2), and secondary development (PR3). Comparative segments were used to analyze xylogenesis in stems: apical meristem with primary development (PS1), secondary development (PS2), and isolated secondary xylem (PS3). Results indicated that only approximately 10% of the genes that were identified to be differentially expressed during xylogenesis were common to both pioneer roots and stems. Despite the dissimilarity in gene expression, however, many fundamental mechanisms were similar, e.g. the pattern of expression of genes involved in the biosynthesis of cell wall proteins, polysaccharides and lignins. While hemicellulose degradation was typical for stems, possibly due to the intensive level of cell wall lignification. Our study is the first to conduct a comprehensive analysis, at the structural and molecular level, of xylogenesis, and clearly reveals the great complexity of molecular mechanisms underlying cell wall formation and modification during xylogenesis.
Project description:Elucidating the genetic control of C3 and C4 photosynthesis. Atriplex rosea (C4) and Atriplex prostrata (C3) were at maturity to compare expression between C3 and C4 in leaves, stems, and roots. Their F1 hybrid leaf was studied at maturity and will aid in identifying regulatory elements involved in C3 and C4 leaf development. Two C3 Atriplex prostrata x C4 Atriplex rosea F3 hybrids (F3003 and F3036) were sequenced at a mature leaf stage.
Project description:Drought is one of the major factor that limits crop production and reduces yield. To understand the early response of plants under nearly natural conditions, pepper plants were grown in a greenhouse and drought stressed by withholding water for one week. Plants adapted to the decreasing water content of the substrate by adjustment of their osmotic potential in roots by accumulation of raffinose, glucose, galactinol and proline. In contrast in leaves levels of fructose, sucrose and also galactinol increased. Due to the water deficit cadaverine, putrescine, spermidine and spermine accumulated in leaves whereas the concentration of polyamines was reduced in roots. These polyamines are suggested to rather act as stress protectants than for osmotic adjustment. To understand the molecular basis of the response to this early drought stress better, four suppression subtractive hybridisation libraries from leaves and roots were constructed. Microarray technique was used to identify differentially expressed genes. A total of 109 unique ESTs were detected. The diversity of the putative functions of all identified genes confirms the complexity of the plant response to drought stress. Keywords: Transcription profiling
Project description:After long-term magnesium-deficiency treatment, 2D electrophoresis and mass spectrum were conducted to investigate different proteiomic profile in Citrus sinensis roots and leaves samples.
Project description:Drought is one of the major factor that limits crop production and reduces yield. To understand the early response of plants under nearly natural conditions, pepper plants were grown in a greenhouse and drought stressed by withholding water for one week. Plants adapted to the decreasing water content of the substrate by adjustment of their osmotic potential in roots by accumulation of raffinose, glucose, galactinol and proline. In contrast in leaves levels of fructose, sucrose and also galactinol increased. Due to the water deficit cadaverine, putrescine, spermidine and spermine accumulated in leaves whereas the concentration of polyamines was reduced in roots. These polyamines are suggested to rather act as stress protectants than for osmotic adjustment. To understand the molecular basis of the response to this early drought stress better, four suppression subtractive hybridisation libraries from leaves and roots were constructed. Microarray technique was used to identify differentially expressed genes. A total of 109 unique ESTs were detected. The diversity of the putative functions of all identified genes confirms the complexity of the plant response to drought stress. Keywords: Transcription profiling Two-condition experiment in roots and leaves, control leaves (CL) vs. drought-stressed leaves (DL) and control roots (CR) vs. drought-stressed roots (DR). Biological replicates: 4 control (1-4), drought-stressed (1-4), independently grown and harvested. One swap replicate per array.
Project description:Qualitative metabolomics study on leaves, roots and acorns from Quercus ilex plantlets. We analyzed polar(metanol:water) and apolar (chloroform) fractions.
Project description:Illumina 100bp single end sequencing was used to profile the transcriptomes of wild type (Columbia) and opt3-2 mutant Arabdiopsis leaves and roots under hydroponic conditions ( 4 weeks old, bolting stage). Sequencing resulted in 381 million uniquely mapping reads accross 36 libraries. Each sample was barcoded and divided into three sequencing lanes, while each genotype/tissue combination is represented by 3 biological replicates consisting of 3-4 individual plants (2 genotypes x 2 tissues x 3 biological replicates x 3 technical replicates = 36 libraries). Our results show the leaves and roots of the opt3-2 mutant have different iron sensing transcriptional programs in place which is independent of the iron status of the plant.
Project description:au08-04_dfo - analysis of deferoxamine treated leaves and roots - What are the effects of the siderophore deferoxamine on Arabidopsis leaves and roots? - Plants were allowed to grow for 5-6 weeks. The nutrient solution contains 0.25 mM Ca(NO3)2.4H2O, 1mM KH2PO4, 0.5 mM KNO3, 1mM MgSO4.7H2O, 50 µM H3BO3, 19 µM MnCl2.4H2O, 10 µM ZnCl2, 1 µM CuSO4.5H2O, 0.02 µM Na2MoO4.2H2O and 50 µM FeNa-EDTA. Plants were subjected to an 8 h light/16 h dark cycle, at 19°C, with 70% relative humidity. Leaves of six week old hydroponically grown A. thaliana Col0 plants were infiltrated with 1mM deferoxamine or sterile distilled water. Leaves were harvested 7 and 24 h.p.i. Keywords: time course,treated vs untreated comparison