Project description:In most organisms biological processes are partitioned, or phased to specific times over the day through interactions between external cycles of temperature (thermocycles) and light (photocycles), and the endogenous circadian clock. This orchestration of biological activities is achieved in part through an underlying transcriptional network. To understand how thermocycles, photocycles and the circadian clock interact to control time of day specific transcript abundance in Arabidopsis thaliana, we conducted four diurnal and three circadian two-day time courses using Affymetrix GeneChips (ATH1). All time courses were carried out with seven-day-old seedlings grown on agar plates under thermocycles (HC, hot/cold) and/or photocycles (LD, light/dark), or continuous conditions (LL, continuous light; DD, continuous dark, HH, continuous hot). Whole seedlings (50-100), including roots, stems and leaves were collected every four hours and frozen in liquid nitrogen. The four time courses interrogating the interaction between thermocycles, photocycles and the circadian clock were carried out as two four-day time courses. Four-day time courses were divided into two days under diurnal conditions, and two days under circadian conditions of continuous light and temperature. Thermocycles of 12 hours at 22C (hot) and 12 hours at 12C (cold) were used in this study. The two time courses interrogating photoperiod were conducted under short days (8 hrs light and 16 hrs dark) or long days (16 hrs light and 8 hrs dark) under constant temperature. In addition, the photoperiod time courses were in the Landsberg erecta (ler) accession, in contrast to the other time courses that are in the Columbia (col) background. The final time course interrogated circadian rhythmicity in seedlings grown completely in the dark (etiolated). Dark grown seedlings were synchronized with thermocycles, and plants were sampled under the circadian conditions of continuous dark and temperature.
Project description:Plant growth and survival depends to a large extent on the diurnal regulation of cellular processes. Although extensively studied at the transcript level, notably less is known about diurnal fluctuations at the protein level. Here, we report a high-resolution quantitative time-course of the Arabidopsis rosette proteome and phosphoproteome over a 12 h light:12 h dark diel cycle. We monitored the proteome every 2 h and the phosphoproteome immediately before and after the light-to-dark and dark-to-light transitions. Notably, we quantified nearly 5000 proteins and 1800 phosphopeptides, of which 288 and 225, respectively, were found to fluctuate over the time-course. Diurnal proteome and phosphoproteome changes were related to diverse biological processes, including protein translation, light detection, photosynthesis, metabolism and transport. Together, these datasets represent the most comprehensive proteomic analysis of Arabidopsis rosettes to date, allowing us to make multi-level inferences about the diurnal regulation of key cellular plant processes plants.
Project description:Photoperiod is a circannual signal measured by biological systems to align growth and reproduction with the seasons. To understand the effect of photoperiod of gene expression in Arabidopsis thaliana in the absence of exogenous sugar under constant light intensity, we performed time course mRNA-seq analysis on 13-day old seedlings across three photoperiods with triplicates to identify photoperiod-regulated genes.
Project description:This experiment profiled a time series of gene expression in leaf 7 of Arabidopsis thaliana plants grown in a controlled environment under 8 h light: 16 h dark (i.e. short days) to compare to the profiles analysed in Breeze et al. (2011) Plant Cell 23(3):873-94 under long day conditions.
Project description:To investigate the response of Arabidopsis thaliana plants to non-freezing, cool temperatures, we subjected four week old plants to various chilling temperatures at defined times during the diurnal cycle to control for diurnal effects on transcription. From the same plants, metabolites and enzyme activities were measured as well. Interestingly a gradual change could be observed over a wide range of temperatures. Some of which could be attributed to the CBF program. Experiment Overall Design: Arabidopsis thaliana rosettes from 4 week old plants at a time point four hours into the light-period were transfered to various "chilling" temperatures (20 [control], 17, 14, 12, 10 and 8°C] and harvested after 6 or 78 hours (both 10 hours into the light period). Experiment Overall Design: 6 continuous treatments X 2 timepoints X 2 replicates
Project description:Arabidopsis thaliana circadian and light signaling mutants have long hypocotyls under light/dark cycles. In order to determine if aberrant hypocotyl growth is due to time of day specific miss-expression of growth associated transcripts we conducted time course microarray experiments in the lux-2, lhy and phyB-9 mutants. The mutants and their parental genotypes were grown on plates under either intermediate days (12 hours light and 12 hours dark) for lux-2, or short day (8 hrs of light and 16 hrs of dark) for lhy and phyB-9, for seven days and tissue was collected every four hours over one day.