Project description:Time-course transcriptional profiling of rice leaf of the temperature shift experiment in a growth chamber. This experiment was performed to validate the results of field transcriptomic modeling. Rice leaves (cv. Norin8) were collected at 2:00 and 14:00 on the day -1, 2, 4 and 6 from the temperature shift (diurnal cycle temperature condition to continuous temperature condition). Two biological replicates for each sampling time point.
Project description:Poplar (Populus trichocarpa, clone Nisqually-1) plants were grown in a Conviron PGR 15 growth chamber using precise control of temperature, light, and humidity. Diurnal (driven) conditions included 12L:12D light cycles and 25C/12C thermocycles in three different combinations. These were: photocycles (LDHH), 12 hrs. light (L)/12 hrs. dark (D) at a constant temperature (25C; HH); photo/thermocycles (LDHC): 12 hrs. light (L) /12 hrs. dark (D) with a high day temperature (25C) and a low night temperature (12C); and thermocycles (LLHC): continuous light (LL) with 12 hrs. high/12 hrs. low temperature (25C, day; 12C, night). Light intensity and relative humidity were 700 micromol m-2s-2 and 50%, respectively. Three-month-old poplar plants were entrained for at least one week under the respective condition prior to initiation of each experiment. Leaves and stems from individual poplar plants were collected every four hours for 48 hrs in driven (diurnal) conditions followed by a two day freerun spacer under continuous light/temperature followed by two additional days of sampling under the same continuous free run condition.
Project description:Rice (Oryza sativa, spp. Indica, cv. 93-11) plants were grown in a Conviron PGR 15 growth chamber using precise control of temperature, light, and humidity.<br>Diurnal (driven) conditions included 12L:12D light cycles and 31C/20C thermocycles in three different combinations. These were: photocycles (LDHH), 12 hrs. light (L)/12 hrs. dark (D) at a constant temperature (31C; HH); photo/thermocycles (LDHC): 12 hrs. light (L) /12 hrs. dark (D) with a high day temperature (31C) and a low night temperature (20C); and thermocycles (LLHC): continuous light (LL) with 12 hrs. high/12 hrs. low temperature (31C, day; 20C, night). Light intensity and relative humidity were 1000 micromol m-2s-2 and 60%, respectively.<br>Three-month-old rice plants were entrained for at least one week under the respective condition prior to initiation of each experiment. Leaves and stems from individual rice plants were collected every four hours for 48 hrs in driven (diurnal) conditions followed by a two day freerun spacer under continuous light/temperature followed by two additional days of sampling under the same continuous free run condition.
Project description:Transcript profiling was performed on samples derived from plants grown under long day conditions. Time series were harvested under diurnal (L/D; light/dark cycles) at control temperature (20 C) and cold (4 C); and under circadian conditions (L/L; continuous light) at control temperature (20 C). Leaves were sampled at time 0 and after 2 h (to coincide with light-dark transitions) and then every 4 h until 58 h.
Project description:Rice (Oryza sativa, ssp. Japonica, cv. Nipponbare 1) plants were grown in a Conviron PGR 15 growth chamber using precise control of temperature, light, and humidity.<br>Diurnal (driven) conditions included 12L:12D light cycles and 31C/20C thermocycles in three different combinations. These were: photocycles (LDHH), 12 hrs. light (L)/12 hrs. dark (D) at a constant temperature (31C; HH); photo/thermocycles (LDHC): 12 hrs. light (L) /12 hrs. dark (D) with a high day temperature (31C) and a low night temperature (20C); and thermocycles (LLHC): continuous light (LL) with 12 hrs. high/12 hrs. low temperature (31C, day; 20C, night). Light intensity and relative humidity were 1000 micromol m-2s-2 and 60%, respectively.<br>Three-month-old rice plants were entrained for at least one week under the respective condition prior to initiation of each experiment. Leaves and stems from individual rice plants were collected every four hours for 48 hrs in driven (diurnal) conditions followed by a two day freerun spacer under continuous light/temperature followed by two additional days of sampling under the same continuous free run condition.<br>
Project description:au14-07_clock - llhh clock transcriptome - Correlate clock-controlled diurnal gene expression changes with H2Bub chromatin mark changes on a genome-wide scale. - Wild type seedlings(Col-0)have been grown under Light/Dark conditions(12 h Light:12 h Dark)and thermocycles(23°C day:19°C night).After 10 days of entrainment, the conditions were switched to continuous light and temperature (LLHH) for 2 days. Seedlings have been harvested the 2nd day after the switch at Zeitgeber time 24 and 36 that correspond to dawn and dusk, respectively. llhh clock transcriptome-LLHH clock transcriptome.
Project description:The extent to which light-saturated net CO2 assimilation (An) and leaf dark respiratory CO2 release (Rdark) jointly acclimate to abrupt and sustained changes in temperature (T) in rice (Oryza sativa L.) is unclear, as are the underlying mechanisms associated with thermal acclimation. To further our understanding of how sustained changes in temperature affect the carbon economy of rice, hydroponically-grown plants of the IR64 cultivar were developed at 30/25°C (day/night) in a temperature-controlled greenhouse before being shifted to 25/20°C or 40/35°C. Leaf RNA expression, protein abundance, sugar and starch content, gas-exchange and elongation rates were measured on pre-existing leaves (PE) already developed at 30/25°C, or leaves newly-developed (ND) subsequent to temperature transfer.
Project description:Temperature has a major role in plant growth and survival, for example wheat yields decrease by about 6% for every 1°C rise in global temperature [1]. High temperatures induce the expression of protective chaperones and modulate growth responses. Key players in the heat protection response are transcription factors of the HEAT SHOCK FACTOR A1 (HSFA1) family [2]. However the pathways that activate the HSFA1 class TFs, and how these perceive temperature and integrate it with other environmental signals are not clear. Plants are exposed to considerable diurnal temperature variation, and have evolved pathways to anticipate likely future conditions. For example, the cold response pathway is gated by the circadian clock, enabling the degree of responsiveness to cold to be controlled in the context of the environment [3, 4] and genes promoting elongation growth and flowering in response to warm temperature are induced during the night via thermosensory phytochromes [5 ,6]. It is not known in Arabidopsis if the warm temperature protective pathways are gated. In this study we find that there is strong diurnal variation in the heat stress response of Arabidopsis, and we show that this correlates with the expression of HSP70 in the day night cycle. The dark to light transition is in fact sufficient to robustly induce expression of warm temperature protective genes such as HSP70. A forward genetic screen with a HSP70-Luciferase reporter line revealed genes necessary for controlling this process and identified a central role for chloroplast signalling in the warm temperature response that accounts for diurnal variation in thermotolerance.
Project description:The central role of transcriptional regulation in integrating various low temperature response mechanisms has been established in Arabidopsis, where the CBF/DREB regulon plays a prominent role during acclimation. Rice is sensitive to chilling but many japonica cultivars can survive continuous exposure to as low as 10oC for up to 7 days during the most critical stage of seedling establishment better than most indica cultivars. The transcriptional regulatory networks that define this variation have not been studied in detail as cold acclimation has been scrutinized in Arabidopsis. Towards the comparison of the compositional complexity of low temperature response regulons of rice and Arabidopsis, we used the cultivar Nipponbare for genome-wide survey of regulatory clusters by integrative analysis of promoter architectures and temporal expression profiles during exposure to 10oC at narrow time intervals. Temporal profiles revealed major clusters of genes that were induced within the initial 24 hours. These clusters were further defined by common features of having either CRT/DRE-like elements, as1/ocs-like elements or both in their promoters. Genes containing as1/ocs-like elements with or without CRT/DRE, but not those containing only CRT/DRE-like elements were induced by exogenous H2O2 but not by ABA at ambient temperature, suggesting that they belong to a potential regulon (ROS-bZIP – as1/ocs module) that responds to elevated levels of reactive oxygen species (ROS) during the initial stages of stress. Parallel analysis of transcription factors during the initial 12 hours revealed candidate regulator(s) of this putative early response regulon. Cultivar-specific expression signatures of selected members of this regulatory cluster were also positively correlated with genotypic variation in chilling tolerance. We hypothesized that the ROS-bZIP – as1/ocs cluster has important roles in configuring the transcriptome of rice seedlings during the early stages of chilling stress and it appears to be independent of ABA and functions in parallel to the CBF/DREB regulon. Keywords: time course (response to low temperature)