Project description:Plants of three different genotypes (FRI FLC, FRI flc and fri flc) were induced to flowering by shifting from short day conditions to long day conditions. FRI=FRIGIDA, FLC=FLOWERING LOCUS C.
Project description:Examination of Columbia-O wildtype and flk mutant tissues under the following conditions: 7 day-old long-day grown, collected 1hr after dawn (exp3: GSM26236-GSM26241); 16 day-old continuous-light-grown (exp2: GSM26230-GSM26235); 16 day-old long-day grown, collected at 16hrs after dawn (exp1: GSM26224-GSM26229). Keywords = Arabidopsis Keywords = flowering Keywords = flk Keywords: other
Project description:To investigate how HDC1, HDA6, and HDA19 regulate gene transcription and flowering time in long day conditions, we performed RNA deep sequencing (RNA-seq) to compare the transcriptomes of wild type, hdc1, hda6, and hda19 mutants grown in long day conditions.
Project description:Plants adapt to the prevailing photoperiod by optimally adjusting growth and flowering to the availability of energy. When Arabidopsis thaliana plants are grown in long days individual leaf growth is favoured, whereas whole plant leaf area is decreased because of the rapid shift to floral stages and, consequently, the low number of total leaves. To understand the molecular profiles of adaptation to long-day conditions we profiled Arabidopsis leaf number six of plants grown in 16 hours of light at four developmental stages both at the end of the day and the end of the night and compared the profiles to those acquired in short day conditions.
Project description:affy_sunflower_2011_02 - affy_sunflower_2011_02 - The early sowing constitutes an alternative strategy to avoid drought occurring during flowering and post-flowering periods and responsible for decrease in sunflower production. In French cropping system, early sowing is associated to low temperature period and frost during first development stages in sunflower. Knowledge about metabolism of frost acclimation must be performed to supply tools for breeding programs in sunflower. The aim of our experiment is to unravel the transcriptional regulation underpinning frost tolerance in sunflower-5 genotypes of sunflower were grown in a growth chamber 1 (23°C day/18°C night, 63% air humidity, 14 hours day photoperiod). At the stage of 6 leaves well-developed, 12 plants of each genotype were subjected to cold acclimation (+4°C during 2 days) in another growth chamber 2. Then, these plants were subjected to 2 nights at -3°C (frost treatment). Chlorophylle fluorescence, Osmotic potential, Relative electrolyte leakage were then determined in the following conditions : - 6th October on 6 plants X 5 genotypes from growth chamber 1 (C1) - 6th October on 6 plants X 5 genotypes from growth chamber 2 (S1) - 11th October on 6 plants X 5 genotypes from growth chamber 1 (C2) - 11th October on 6 plants X 5 genotypes from growth chamber 1 (S2)
Project description:We were interested in changes in small RNA abundance changes in response to developmental transitions in Arabidopsis thaliana shoots, with special focus on vegetative phase change. We specifically wanted to separate the temporal changes in gene expression that result from vegetative phase change and those from flowering. Because of the close timing between the juvenile-to-adult and adult-to-reproductive developmental transitions in Arabidopsis grown under long day conditions, we used the late-flowering genotype FRI;FLC developed by the lab of Richard Amasino by introgressing the FRI allele from Sf-2 into the Col-0 genetic background, which is fri;FLC. For the early flowering genotype, we used FRI;flc-3, also developed by the Amasino lab by EMS-mutagenizing FRI;FLC, identifying early flowering mutants, and backcrossing multiple times to eliminate other EMS-induced mutations. The onset of vegetative phase change in FRI;FLC and FRI;flc-3 under our growth conditions was identical, but the progression was slower in FRI;FLC. By sequencing small RNAs from shoot apices at different time points and fully-expanded leaves at different positions on the shoot and comparing the results between the two genotypes, we were able to obtain a clear picture of changes in small RNA abundance in response to vegetative phase change and flowering in Arabidopsis. For the small RNA samples, we performed two replicates using two different indices in the 5'-adapter and ran each replicate pair on the same sequencing lane. For the cotyledon and leaf samples we only performed one replicate using the same index for all samples because we obtained significantly different results with the two adapters used for the shoot apices, preventing us from using them as true replicates.
Project description:Flowering in plants is a very dynamic and synchronized process where various cues including age, day-length, temperature and endogenous hormones fine-tune the timing of flowering for reproductive success. Arabidopsis thaliana is a facultative long day plant where long-day (LD) photoperiod promotes flowering. Arabidopsis still flowers under short-day (SD) conditions, albeit much later than LD conditions. Although, factors regulating the photoperiodic LD pathway have been extensively investigated, the SD pathway is much less understood. Here we identified a critical transcription factor called bHLH93 (basic Helix-Loop-Helix 93) that is essential to induce flowering specifically under SD conditions in Arabidopsis. bhlh93 mutants do not flower from primary meristem under SD conditions, but flowers similar to wild type under LD conditions. The late flowering phenotype is rescued by exogenous application of GA, suggesting that bHLH93 acts upstream of GA pathway to promote flowering. Double mutant studies showed that bhlh93 is epistatic to phyB and soc1 genes under SD conditions. bHLH93 is expressed at the meristematic regions and its expression peaks at 8 hours after dawn under SD conditions. As expected, the bHLH93 is localized in the nucleus. Taken together, these data suggest that bHLH93 is a key transcription factor necessary for Arabidopsis thaliana to evolve as a facultative plant.
Project description:The timing of reproductive development determines spike architecture and thus yield in temperate grasses such as barley (Hordeum vulgare L.). Reproductive development in barley is controlled by the photoperiod response gene Ppd-H1 which accelerates flowering time under long-day (LD) conditions. A natural mutation in Ppd-H1 prevalent in spring barley causes a reduced photoperiod response, and thus, late flowering under LD. However, it is not very well understood how LD and Ppd-H1 control pre-anthesis development, and thus spike architecture and yield in barley. We performed a detailed morphological analysis of the pre-anthesis development in the spring barley cultivar Scarlett and its wild barley derived introgression line S42-IL107, carrying the photoperiod responsive Ppd-H1 allele. Characterization of shoot apex development in these genotypes indicated that floral transition and initiation of floral primordia occurred under LD (16h light/ 8h dark) and short day (SD, 8h light/ 16h dark) conditions, while inflorescence and seed development strictly required LDs. Additionally, a fast photoperiod response in the presence of the dominant Ppd-H1 allele promoted floret fertility under LDs. To characterize the effects of the photoperiod and allelic variation at Ppd-H1 on gene expression during pre-anthesis development we performed RNA sequencing of leaves and developing main shoot apices during the vegetative phase and early stages of inflorescence development in Scarlett and S42-IL107 grown under SD and LD conditions. Main shoot apices of both genotypes were sampled at defined developmental stages, i.e. Waddington stage W0.5, W1.0, W2.0 and W3.5, respectively. Leaf samples were harvested from plants before (W1.0) and after floral transition (W2.0). We identified genes that were specifically regulated at floral transition independent of day-length and Ppd-H1 and thus may serve as markers for the staging of floral transition. Furthermore, we identified transcripts differentially expressed between photoperiods and between genotypes in leaves and in shoot apices. This set of transcripts might act as candidates downstream of Ppd-H1 and are correlated with the promotion of shoot apex development and higher floret fertility under LD and in the presence of the photoperiod responsive Ppd-H1 allele.
Project description:Wild type and mutanat Arabiposis plants grown in short days (9L:15D) for 30 days at 21°C, then shifted to long days (16L:8D). Genotypes: Columbia wild type (Col-0) Landsberg erecta (Ler) leafy-12 (lfy-12, in Col-0) constans-2 (co-2, in Ler) flowering locus T-2 (ft-2, in Ler) Time points: 0, 3, 5, and 7 days after shift to long days Keywords = flowering Keywords: time-course