Functional characterization of genes/proteins differentially expressed in phototrophic and heterotrophic tissues in Arabidopsis thaliana mutants lacking chloroplastic and cytosolic fructose-1,6-bisphosphatase genes
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE32522 | GEO | 2012/05/04
SECONDARY ACCESSION(S): PRJNA147835
REPOSITORIES: GEO
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Project description:Photosynthesis is arguably the most important biological process on earth. In plants, energy harvested in photosynthesis is converted into sugar and starch, which are important products from species with agronomic interest. During the photosynthesis in the chloroplast, the intermediate carbon metabolites (triose phosphates) produced by the Calvin cycle can either be exported to the cytosol for sucrose synthesis or stay in the chloroplast for starch synthesis (formation). Two fructose-1,6-bisphosphatase (FBPase) enzymes, the chloroplastidial (cpFBPaseI) and the cytosolic (cyFBPase) isoforms, catalyse the first irreversible step during the conversion of triose phosphate to starch or sucrose, respectively. Recently, another cpFBPase isoform (cpFBPaseII) with unknown function was identified. It has been reported that the reduction of cyFBPase or cpFBPaseI activity leads to an alteration in starch and sucrose content. In our laboratory, Arabidopsis thaliana knock-out mutants for the cyFBPase and cpFBPaseI are now available. The objective this research project is to identify and functionally characterize genes differentially expressed in Arabidopsis thaliana knock-out mutants lacking FBPase genes. We make use of high throughput methodologies, such as the transcriptomic and proteomic analyses which represent invaluable tools to identify new loci responsible for agronomically important traits. Three independent biological replicates were used for each type of sample. Three hybridizations were performed, representing the three independent biological replicates, being one of them a dye swap
2012-05-03 | E-GEOD-32522 | biostudies-arrayexpress
Project description:The triose-phosphate/phosphate translocator (TPT) of the chloroplast inner envelope membrane mediates the counter-exchange of stromal triose phosphates derived from CO2 fixation with cytosolic phosphate, thus providing the cytosol with precursors for sucrose synthesis. We have isolated an Arabidopsis mutant (tpt-1) in which the gene encoding TPT is disrupted by a T-DNA insertion. During growth in low light tpt-1 plants are phenotypically normal, but in high light photosynthesis is inhibited and growth is retarded relative to wildtype. This mutant compensates for the absence of TPT by diverting photosynthate into starch which is hydrolysed and exported from the chloroplast as glucose that is subsequently phosphorylated by hexokinase. In low light the capacity of the pathway of starch synthesis is sufficient to accommodate the normal rate of CO2 fixation, but in high light it is unable to match the potential rate of CO2 fixation. Consequently, in high light-grown plants there are measurable effects on the redoxstate of several components. Thus, the tpt-1 mutation influences the carbohydrate status within the cell, alters the form in which carbon is received by the cytosol, and changes the redox signals that are important in photosynthetic acclimation. Method: Plants will be grown in a 8h light:16h dark regime at both 400 and 100 µmol PAR m-2 s-1. Total RNA will be extracted from pools of individual illuminated leaves from at least eight plants at growth stage 3.70. Leaves will be harvested 2 h into the photoperiod to maximise differences between plant lines in the expression of genes of photosynthesis and carbohydrate metabolism. We anticipate that expression of many genes will be affected by the absence of TPT and by changes in light intensity. However, by comparing differences in transcript levels between wildtype and TPT mutant grown in high light with the differences that occur in plants grown in low light we will discriminate between genes whose expression is affected by changes in the pattern of carbohydrate metabolism and those influenced by redox poise of the thylakoid photochemical components. These comparisons will also highlight genes affected by recently identified regulatory interactions between sugar-sensing and redox-sensing. A genome-wide expression study will establish the extent to which gene expression is altered by the absence of TPT in leaves, and will provide the basis for more detailed analysis of a selected range of transcripts whose levels of expression differ between plant lines.
2008-02-15 | E-NASC-69 | biostudies-arrayexpress
Project description:The triose-phosphate/phosphate translocator (TPT) of the chloroplast inner envelope membrane mediates the counter-exchange of stromal triose phosphates derived from CO2 fixation with cytosolic phosphate, thus providing the cytosol with precursors for sucrose synthesis. We have isolated an Arabidopsis mutant (tpt-1) in which the gene encoding TPT is disrupted by a T-DNA insertion. During growth in low light tpt-1 plants are phenotypically normal, but in high light photosynthesis is inhibited and growth is retarded relative to wildtype. This mutant compensates for the absence of TPT by diverting photosynthate into starch which is hydrolysed and exported from the chloroplast as glucose that is subsequently phosphorylated by hexokinase. In low light the capacity of the pathway of starch synthesis is sufficient to accommodate the normal rate of CO2 fixation, but in high light it is unable to match the potential rate of CO2 fixation. Consequently, in high light-grown plants there are measurable effects on the redoxstate of several components. Thus, the tpt-1 mutation influences the carbohydrate status within the cell, alters the form in which carbon is received by the cytosol, and changes the redox signals that are important in photosynthetic acclimation.Plants will be grown in a 8h light:16h dark regime at both 400 and 100 õmol PAR m-2 s-1. Total RNA will be extracted from pools of individual illuminated leaves from at least eight plants at growth stage 3.70. Leaves will be harvested 2 h into the photoperiod to maximises differences between plant lines in the expression of genes of photosynthesis and carbohydrate metabolism. We anticipate that expression of many genes will be affected by the absence of TPT and by changes in light intensity. However, by comparing differences in transcript levels between wildtype and TPT mutant grown in high light with the differences that occur in plants grown in low light we will discriminate between genes whose expression is affected by changes in the pattern of carbohydrate metabolism and those influenced by redox poise of the thylakoid photochemical components. These comparisons will also highlight genes affected by recently identified regulatory interactions between sugar-sensing and redox-sensing. A genome-wide expression study will establish the extent to which gene expression is altered by the absence of TPT in leaves, and will provide the basis for more detailed analysis of a selected range of transcripts whose levels of expression differ between plant lines. Experimenter name = Robin Walters; Experimenter phone = 01865 275000; Experimenter fax = 01865 275074; Experimenter address = Dept of Plant Sciences; Experimenter address = University of Oxford; Experimenter address = South Parks Road; Experimenter address = Oxford; Experimenter zip/postal_code = OX1 3RB; Experimenter country = UK Experiment Overall Design: 12 samples were used in this experiment
2008-06-14 | E-GEOD-5737 | biostudies-arrayexpress
Project description:Fructans represent the major component of water soluble carbohydrates (WSCs) in the maturing stem of temperate cereals and are an important temporary carbon reserve for grain filling. Theoretically, genotypic variation in carbon reserve accumulation is determined by relative carbon availability and demand at the whole plant level. To evaluate the importance of source carbon availability in fructan accumulation and its associated molecular mechanisms, we performed comparative analyses of individual WSC components and the expression profiles of genes involved in major carbohydrate metabolism and photosynthesis in flag leaves of recombinant inbred lines derived from a cross between wheat cultivars Seri M82 and Babax (SB lines). High sucrose levels in the mature flag leaf (source carbon organ) were found to be positively associated with WSC and fructan concentrations in both the leaf and stem of SB lines in several field trials. Analysis of Affymetrix expression array data revealed that high leaf sucrose lines grown in abiotic-stress-prone environments had high expression levels of a number of genes in the leaf involved in the sucrose synthetic pathway and photosynthesis, such as Calvin cycle genes, antioxidant genes involved in the removal of chloroplast H2O2 and genes involved in energy dissipation. The expression of the majority of genes involved in fructan and starch synthetic pathways were positively correlated with sucrose levels in the leaves of these SB lines. 8 genotypes of recombinant inbred lines Seri M82 x Babax with 2 biological replicates per genotype. Grown in the field under irrigated conditions.
2013-04-30 | E-GEOD-37675 | biostudies-arrayexpress
Project description:To investigate whether the transcriptional response to carbon (C) depletion and sucrose re-addition depend on the duration of C-depletion, Arabidopsis thaliana seedlings growing in liquid culture in weak continuous light were harvested 3, 6, 12, 24, 48 and 72 h after removing sucrose from the medium, and 30 min after resupplying sucrose at each of these times. After removing sucrose, soluble sugars fell strongly within 3 h, and starch was gradually depleted over 24 h, and hexose phosphates and ATP declined gradually over 72 h. Expression profiling using ATH arrays pointed to Overall the transcriptional response pointed to early transcriptional remodelling of metabolism to conserve C, followed by induction of photosynthesis and pathways that recycle C, and repression of growth-related processes. The time-dependent transcriptional response to C-depletion differed from that during a light/dark cycle and an extended night. Re-supplying sucrose for 30 min led to near-complete recovery of seedling sucrose levels, partial recovery of reducing sugars and phosphorylated intermediates, but no immediate change of starch or ATP. The rapid transcriptional response to sucrose readdition was conserved across the entire C-depletion time course, became larger with time. , and was highly enriched for regulatory genes. Whilst there was a rapid decrease of many C-depletion-induced transcripts, fewer transcripts increased. The majority of the transcripts that responded rapidly after resupplying sucrose also decreased after treating C-depleted seedlings with the transcriptional inhibitor cordycepin A, pointing to an important role for transcript turnover in the rapid response to sucrose.
2015-10-12 | E-MTAB-3143 | biostudies-arrayexpress
Project description:Fructans represent the major component of water soluble carbohydrates (WSCs) in the maturing stem of temperate cereals and are an important temporary carbon reserve for grain filling. Theoretically, genotypic variation in carbon reserve accumulation is determined by relative carbon availability and demand at the whole plant level. To evaluate the importance of source carbon availability in fructan accumulation and its associated molecular mechanisms, we performed comparative analyses of individual WSC components and the expression profiles of genes involved in major carbohydrate metabolism and photosynthesis in flag leaves of recombinant inbred lines derived from a cross between wheat cultivars Seri M82 and Babax (SB lines). High sucrose levels in the mature flag leaf (source carbon organ) were found to be positively associated with WSC and fructan concentrations in both the leaf and stem of SB lines in several field trials. Analysis of Affymetrix expression array data revealed that high leaf sucrose lines grown in abiotic-stress-prone environments had high expression levels of a number of genes in the leaf involved in the sucrose synthetic pathway and photosynthesis, such as Calvin cycle genes, antioxidant genes involved in the removal of chloroplast H2O2 and genes involved in energy dissipation. The expression of the majority of genes involved in fructan and starch synthetic pathways were positively correlated with sucrose levels in the leaves of these SB lines.
2013-04-30 | GSE37675 | GEO
Project description:The triose-phosphate/phosphate translocator (TPT) of the chloroplast inner envelope membrane mediates the counter-exchange of stromal triose phosphates derived from CO2 fixation with cytosolic phosphate, thus providing the cytosol with precursors for sucrose synthesis. We have isolated an Arabidopsis mutant (tpt-1) in which the gene encoding TPT is disrupted by a T-DNA insertion. During growth in low light tpt-1 plants are phenotypically normal, but in high light photosynthesis is inhibited and growth is retarded relative to wildtype. This mutant compensates for the absence of TPT by diverting photosynthate into starch which is hydrolysed and exported from the chloroplast as glucose that is subsequently phosphorylated by hexokinase. In low light the capacity of the pathway of starch synthesis is sufficient to accommodate the normal rate of CO2 fixation, but in high light it is unable to match the potential rate of CO2 fixation. Consequently, in high light-grown plants there are measurable effects on the redoxstate of several components. Thus, the tpt-1 mutation influences the carbohydrate status within the cell, alters the form in which carbon is received by the cytosol, and changes the redox signals that are important in photosynthetic acclimation.Plants will be grown in a 8h light:16h dark regime at both 400 and 100 µmol PAR m-2 s-1. Total RNA will be extracted from pools of individual illuminated leaves from at least eight plants at growth stage 3.70. Leaves will be harvested 2 h into the photoperiod to maximises differences between plant lines in the expression of genes of photosynthesis and carbohydrate metabolism. We anticipate that expression of many genes will be affected by the absence of TPT and by changes in light intensity. However, by comparing differences in transcript levels between wildtype and TPT mutant grown in high light with the differences that occur in plants grown in low light we will discriminate between genes whose expression is affected by changes in the pattern of carbohydrate metabolism and those influenced by redox poise of the thylakoid photochemical components. These comparisons will also highlight genes affected by recently identified regulatory interactions between sugar-sensing and redox-sensing. A genome-wide expression study will establish the extent to which gene expression is altered by the absence of TPT in leaves, and will provide the basis for more detailed analysis of a selected range of transcripts whose levels of expression differ between plant lines. Experimenter name = Robin Walters Experimenter phone = 01865 275000 Experimenter fax = 01865 275074 Experimenter address = Dept of Plant Sciences Experimenter address = University of Oxford Experimenter address = South Parks Road Experimenter address = Oxford Experimenter zip/postal_code = OX1 3RB Experimenter country = UK Keywords: growth_condition_design; genetic_modification_design;
2007-01-08 | GSE5737 | GEO
Project description:In this study, we have used the comparative transcriptomic and proteomic approaches to decipher the changes in genes and protein abundances in cigar tobacco leaves under LL. In this study, DEGs and DEPs related to glycolysis, starch and sucrose metabolism, tyrosine metabolism, photosynthesis-antenna proteins, and photosynthesis pathways are significantly enriched. This study offers novel insights into both transcriptome and proteome levels response mechanisms under different light intensities.
2022-08-26 | GSE211923 | GEO
Project description:Chloroplast, the energy organelle unique to plants and green algae, performs a wide range of functions including photosynthesis and biosynthesis of metabolites. However, as the most important tuber crop worldwide, the potato (Solanum tuberosum) chloroplast proteome has not been explored. Here, we use Percoll density gradient centrifugation to isolate intact chloroplasts from leaves of potato cultivar E3 and establish a reference proteome map of potato chloroplast by bottom-up proteomics. A total of 1834 non-redundant proteins, including 51 proteins encoded by the chloroplast genome, were identified in the chloroplast proteome. Extensive sequence-based localization prediction revealed over 62% of proteins to be chloroplast resident by at least one algorithm. A total of 16 proteins were selected for evaluating the prediction result by transient fluorescence assay and confirmed that 14 of them were distributed on distinct internal compartments of the chloroplast. In addition, 136 phosphorylation sites were identified in 61 proteins encoded by chloroplast proteome. Furthermore, by a comparative analysis between chloroplast and previously reported amyloplast proteomes, we reconstruct the starch metabolic pathways in the two different types of plastids. Altogether, our results establish a comprehensive proteome map with post-translationally modified sites of potato chloroplast, which would provide the theoretical principle for the research of photosynthesis pathway and starch metabolism.
2022-08-12 | PXD033047 | Pride
Project description:Arabidopsis thaliana shows hybrid vigour (heterosis) in progeny of crosses between Col and C24 accessions (1). Hybrid vigour was evident as early as the mature seeds and in the seedlings 3 days after sowing (DAS). At 3 DAS genes encoding chloroplast-located proteins were significantly overrepresented (187) among the 724 genes which have greater than mid parent values of expression in the hybrid. Many of these genes are involved in chlorophyll biosynthesis and photosynthesis. The rate of photosynthesis was constant per unit leaf area in parents and hybrids. Larger cell sizes in the hybrids were associated with more chloroplasts per cell, more total chlorophyll and more photosynthesis. The increased transcription of the chloroplast-targeted genes was restricted to the 3 to 7 DAS period. At 10 DAS only 118 genes had expression levels different from the expected mid parent value in the hybrid and only 12 of these genes were differentially expressed at 3 DAS. The early increase in activity of genes involved in photosynthesis and the associated phenomena of increase in cell size and number through development, leading to larger leaf areas of all leaves in the hybrid, suggest a central role for increased photosynthesis in the production of the heterotic biomass. In support of this correlation we found that an inhibitor of photosynthesis eliminated heterosis and higher light intensities enhanced both photosynthesis and heterosis. In hybrids with low level heterosis (Ler x Col) chloroplast-targeted genes were not upregulated and leaf areas were only marginally increased. Whole plants in Col, C24, and their F1 hybrids with two replications
2012-03-06 | E-GEOD-36273 | biostudies-arrayexpress