Project description:Adaptation of Lactococcus lactis towards progressive carbon starvation is mediated by three different types of transcriptomic responses: i) global responses, i.e. general decrease of functions linked to bacterial growth and lack of induction of the general stress response, ii) specific responses functionally related to glucose exhaustion, i.e. under expression of central metabolism genes, induction of alternative sugars transport and metabolism genes, induction of arginine deiminase pathway genes and iii) other responses never described previously during carbon starvation. Keywords: stress response, time course
Project description:Using a transgenic line expressing HA-tagged ATAF1 uncovered >400 ChIP-seq peaks in ATAF1-HA plants compared to Col-0 wild-type plants. Only a small sub-set of the candidate peaks could be verified using ChIP-qpcr or EMSA. Among the verified peaks we uncovered the key ABA biosynthetic gene NCED3 as a target of ATAF1
Project description:gene expression profiling in different zones along the gradient of the growing maize leaf balde aover a time course of dirunal cycle and carbon starvation by extension of the night Plants assimilate carbon in their photosynthetic tissues in the light. However, carbon is required during the night, and in non-photosynthetic organs. It is therefore essential that plants manage their carbon resources spatially and temporally and coordinate growth with carbon availability. In growing maize (Zea mays) leaf blades a defined developmental gradient facilitates analyses in the cell division, elongation and mature zones. We investigated the responses of the metabolome and transcriptome and polysome loading, as a qualitative proxy for protein synthesis, at dusk, dawn and 6, 14 and 24 hours into an extended night, and tracked whole leaf elongation over this time course. Starch and sugars are depleted by dawn in the mature zone, but only after an extension of the night in the elongation and division zones. Sucrose recovers partially between 14 and 24 h into the extended night in the growth zones but not the mature zone. The global metabolome and transcriptome track these zone-specific changes in sucrose. Leaf elongation and polysome loading in the growth zones also remain high at dawn, decrease between 6 and 14 h into the extended night and then partially recover indicating that growth processes are determined by local carbon status. The level of sucrose-signaling metabolite trehalose-6-phosphate, and the trehalose-6-phosphate:sucrose ratio are much higher in growth than mature zones at dusk and dawn but fall in the extended night. Candidate genes were identified by searching for transcripts that show characteristic temporal response patterns or contrasting responses to carbon starvation in growth and mature zones. 3 repliucates per time point and leaf region, each pooled form 5 indiviual plants
Project description:For the first time in Lactococcus lactis, amino acid starvation response was characterized. The natural imposition of isoleucine starvation, by its consumption during growth, associated to transcript profiling, allowed defining exhaustively this stress stimulon. It consisted of a general induction of nitrogen metabolism (amino acid biosynthesis and transport, proteolytic system and proteases), a strong repression of genes encoding major physiological activities (translation, transcription, carbon metabolism, purine and pyrimidine biosynthesis and fatty acid metabolism) and the induction of unexpected cross responses to acid, osmotic and oxidative stresses. Keywords: stress response, time course
Project description:Cells must appropriately sense and integrate multiple metabolic resources to commit to proliferation. Here, we report that cells regulate nitrogen (amino acid) and carbon metabolic homeostasis through tRNA U34-thiolation. Despite amino acid sufficiency, tRNA-thiolation deficient cells appear amino acid starved. In these cells, carbon flux towards nucleotide synthesis decreases, and trehalose synthesis increases, resulting in metabolic a starvation-signature. Thiolation mutants have only minor translation defects. However, these cells exhibit strongly decreased expression of phosphate homeostasis genes, mimicking a phosphate-limited state. Reduced phosphate enforces a metabolic switch, where glucose-6-phosphate is routed towards storage carbohydrates. Notably, trehalose synthesis, which releases phosphate and thereby restores phosphate availability, is central to this metabolic rewiring. Thus, cells use thiolated tRNAs to perceive amino acid sufficiency, and balance amino acid and carbon metabolic flux to maintain metabolic homeostasis, by controlling phosphate availability. These results further biochemical explain how phosphate availability determines a switch to a ‘starvation-state’.
Project description:In this study, through a genome-wide transcriptome analysis of wounding in the leaf explant, we identified NAC1 (petunia NAM and Arabidopsis ATAF1, ATAF2, and CUC2) family transcription factor gene that acts in response to wounding and functions in regulation of cell wall metabolism.
Project description:In this study, through a genome-wide transcriptome analysis of wounding in the leaf explant, we identified NAC1 (petunia NAM and Arabidopsis ATAF1, ATAF2, and CUC2) family transcription factor gene that acts in response to wounding and functions in regulation of cell wall metabolism.
Project description:gene expression profiling in different zones along the gradient of the growing maize leaf balde aover a time course of dirunal cycle and carbon starvation by extension of the night Plants assimilate carbon in their photosynthetic tissues in the light. However, carbon is required during the night, and in non-photosynthetic organs. It is therefore essential that plants manage their carbon resources spatially and temporally and coordinate growth with carbon availability. In growing maize (Zea mays) leaf blades a defined developmental gradient facilitates analyses in the cell division, elongation and mature zones. We investigated the responses of the metabolome and transcriptome and polysome loading, as a qualitative proxy for protein synthesis, at dusk, dawn and 6, 14 and 24 hours into an extended night, and tracked whole leaf elongation over this time course. Starch and sugars are depleted by dawn in the mature zone, but only after an extension of the night in the elongation and division zones. Sucrose recovers partially between 14 and 24 h into the extended night in the growth zones but not the mature zone. The global metabolome and transcriptome track these zone-specific changes in sucrose. Leaf elongation and polysome loading in the growth zones also remain high at dawn, decrease between 6 and 14 h into the extended night and then partially recover indicating that growth processes are determined by local carbon status. The level of sucrose-signaling metabolite trehalose-6-phosphate, and the trehalose-6-phosphate:sucrose ratio are much higher in growth than mature zones at dusk and dawn but fall in the extended night. Candidate genes were identified by searching for transcripts that show characteristic temporal response patterns or contrasting responses to carbon starvation in growth and mature zones.
Project description:Using a transgenic line expressing HA-tagged ATAF1 uncovered >400 ChIP-seq peaks in ATAF1-HA plants compared to Col-0 wild-type plants. Only a small sub-set of the candidate peaks could be verified using ChIP-qpcr or EMSA. Among the verified peaks we uncovered the key ABA biosynthetic gene NCED3 as a target of ATAF1 ChIP was performed using anti-HA antibodies on wild-type Col-0 plants and plants expressing HA-tagged ATAF1
Project description:In this study, through a genome-wide transcriptome analysis of wounding in the leaf explant, we identified NAC1 (petunia NAM and Arabidopsis ATAF1, ATAF2, and CUC2) family transcription factor gene that acts in response to wounding and functions in regulation of cell wall metabolism. RNA-Seq analysis of the genes up-regulated by NAC1