Project description:This experiment is intended to provide information about transcriptional changes in the gill of Atlantic salmon during smoltification, in comparison with juvenile salmon not given the appropriate photoperiodic stimuli. Also, transcriptional changes due to osmotic stress (24H salt water challenged) will be recorded. This to better understand the transformation of the gill from a fresh water-type to a salt water-type, and possibly identify novel and important genes that are dependent upon a specific photoperiodic history for their expression. Additionally the data can be used to observe the shift in salt water response as the juvenile salmon goes through smoltification. Experimental workflow: All fish started on 24H light (LL), after one week, half of the fish were moved to short photoperiod (8:16, SP). The rest remained on LL throughout. After eight weeks, half of the fish on short photoperiod were moved back onto 24H light (SPLL). Remaining fish continued under 8:16. After another eight weeks the experiment was ended. Fish were sampled on days 0, 32, 53, 68, 89 and 110. On each sampling occasion fish were sampled directly from fresh water (FW), and from a 24H salt water (SW) stay, transferred the previous day. Weight and length was noted. Gill tissue was the taken and placed in RNAlater. Additionally plasma for measuring hypoosmoregulatory capacity was taken.
Project description:Plants respond to seasonal cues such as the photoperiod, to adapt to current conditions and to prepare for environmental changes in the season to come. To assess photoperiodic responses at the protein level, we quantified the proteome of the model plant Arabidopsis thaliana by mass spectrometry across four photoperiods. This revealed coordinated changes of abundance in the proteins of photosynthesis, primary metabolism and secondary metabolic processes such as pigment biosynthesis, consistent with higher metabolic activity in long photoperiods. Higher translation rates during the day than during the night likely contribute to these changes, but rhythmic RNA profiles will alter their effects. Photoperiodic control of protein levels might be greatest if high translation rates only coincide with high transcript levels in some photoperiods. We term this mechanism ‘translational coincidence’, mathematically model its components, and demonstrate its effect on the Arabidopsis proteome. Datasets from a green alga and a cyanobacterium suggest that this mechanism is general, contributing to the seasonal control of the proteome in many phototrophic organisms, and favouring RNA rhythms even for stable proteins.
Project description:In order to identify genes specifically involved in the photoperiodic control of the mobilisation programme for starch reserve in Arabidopsis thaliana transcription profiling was performed on the following genotypes Columbia wild type (Col-0), CO overexpressor (35S::CO), CO muntant (co-10), GBSSI mutant (gbs-1), aps1 mutant (aps1) and Columbia with sucrose. The different Arabidopsis thaliana genotype seedlings were cultivated in long day conditions (16 h day/ 8 h dark) at 22 C in controlled environment cabinets for two weeks. Samples were collected at ZT 4, immediately frozen in liquid nitrogen and processed.
Project description:The induction of flowering by the photoperiodic pathway (i.e. an increase in daylength) involves the production of systemic signals that induce the transition to reproductive development. In order to evaluate the early events occurring in the roots during the photoperiodic induction of flowering, we harvested the roots of 7 week-old Col-0 Arabidopsis thaliana plants grown plants exposed to a single 22-hour long day. Control plants were maintained under 8-hour short days. Plants were grown in hydroponics and roots tissues were harvested 16 and 22 hours after the beginning of the light period.
Project description:A great majority of plants synchronize flowering with day length. In rice, the most important environmental cue that triggers flowering is the photoperiod. Here, we show that the s73 mutant, identified in a gamma irradiated Bahia collection, displays early flowering and photoperiodic insensitivity due to a null mutation in the SE5 gene, which encodes an enzyme implicated in phytochrome chromophore biosynthesis. s73 mutant plants showed a number of alterations in the characteristic diurnal expression patterns of master genes involved in photoperiodic control of flowering, resulting in up-regulation of Hd3a, the most important floral integrator. Ehd1, an additional rice floral activator, was also highly expressed in the s73 mutant, suggesting that SE5 represses Ehd1 in wild-type plants. Silencing of Ehd1 in both Bahia and s73 backgrounds implies that SE5 regulates Ehd1 expression. The data also indicate that SE5 confers photoperiodic sensitivity through regulation of Hd1. These results provide direct evidence that phytochromes inhibit flowering affecting both Hd1 and Ehd1 flowering pathways.
Project description:We analyzed the transcriptome change during photoperiodic regulation of potato tuber formation 3 samples from longday condition and 2 samples from shortday condition were sequenced
Project description:Seasonal adaptation to changes in light:dark regimes (i.e., photoperiod) allows organisms living at temperate latitudes to anticipate environmental change and adjust their physiology and behavior accordingly. The circadian system has been implicated in measurement and response to changes in photoperiod in nearly all animals studied so far (Saunders, 2011). The use of both traditional and non-traditional model insects with robust seasonal responses has recently genetically demonstrated the central role that clock genes play in photoperiodic response. Yet, the molecular pathways involved in insect photoperiodic responses remain largely unknown. Here, using the Eastern North American monarch butterfly (Reppert et al, 2016; Denlinger et al, 2017), we identified the vitamin A pathway as a novel pathway downstream of the circadian clock mediating insect photoperiod responsiveness. We found that interrupting clock function by disrupting circadian activation and repression abolishes photoperiodic responses in reproductive output, providing a functional link between clock genes and photoperiodic responsiveness in the monarch. Through transcriptomic approaches, we identified a molecular signature of seasonal-specific rhythmic gene expression in the brain, the organ known to function in photoperiodic reception in both Lepidoptera and some flies (Bowen et al, 1984; Saunders & Cymborowski, 1996). Among genes differentially expressed between both long and short photoperiods and between seasonal forms, several were belonging to the vitamin A pathway. The rhythmic expression of all of these genes was abolished in clock-deficient mutants. We also showed that a CRISPR/Cas9-mediated loss-of-function mutation in the pathway’s rate-limiting enzyme, ninaB1, impaired the monarch ability to respond to the photoperiod independently of visual function in the compound eye and without affecting circadian rhythms. Our finding that the vitamin A pathway is a key mediator of photoperiodic responses in insects could have broad implications for understanding the molecular mechanisms underlying photoperiodism.
Project description:A great majority of plants synchronize flowering with day length. In rice, the most important environmental cue that triggers flowering is the photoperiod. Here, we show that the s73 mutant, identified in a gamma irradiated Bahia collection, displays early flowering and photoperiodic insensitivity due to a null mutation in the SE5 gene, which encodes an enzyme implicated in phytochrome chromophore biosynthesis. s73 mutant plants showed a number of alterations in the characteristic diurnal expression patterns of master genes involved in photoperiodic control of flowering, resulting in up-regulation of Hd3a, the most important floral integrator. Ehd1, an additional rice floral activator, was also highly expressed in the s73 mutant, suggesting that SE5 represses Ehd1 in wild-type plants. Silencing of Ehd1 in both Bahia and s73 backgrounds implies that SE5 regulates Ehd1 expression. The data also indicate that SE5 confers photoperiodic sensitivity through regulation of Hd1. These results provide direct evidence that phytochromes inhibit flowering affecting both Hd1 and Ehd1 flowering pathways. Four biological replicates from each genotype (s73 mutant and Bahia wt) were labelled with Cy3 and Cy5 alternatively (2+2) following a dye-swap design. In total, 4 microarrays were hybridized. The supplementary file 'GSE16796_stat_analysis.txt' contains the final statistical analysis of study GSE16796.
Project description:Expression profile of the brain (ventral part of telenchephalon, hypothalamus and pituitary) of medaka (Oryzias latipes) kept under constant photoperiodic conditions were obtained by RNA-seq analysis. Monthly transcriptomes under constant photoperiodic conditions identified 518 circannual genes.