Project description:au13-12_polysome - transcriptome and translatome of arabidopsis wt seeds according to dormancy - Identification of transcripts that are differentially abundant (transcriptome) and transcripts that are addressed to translation (translatome) in imbibed Arabidopsis seeds in relation with dormancy. During imbibition of seeds (16h and 24h in darkness at 25°C, dormant and non-dormant seeds), transcriptome analysis is done on total RNA and translatome analysis on polysomal RNA. - At harvest seeds are dormant. They stay dormant if they are stored at -20°C (D) and become non-dormant (ND) if they are stored 3 weeks at +20°C. Arabidopsis dormant seeds do not germinate at 25°C in darkness while non-dormant seeds do. Total RNA and polysomal RNA (polysomal fractions purified on sucrose gradients) were extracted from imbibed seeds for 16h or 24h at 25°C in darkness (3 biological replicates). Transcriptome and translatome are compared for Dormant vs Non-Dormant for 16h and 24 imbibition. In silico comparison will allow to compare transcriptome and translatome for each point and type of seeds and to compare the time points (16 vs 24h) for each type of sample.
Project description:au13-12_polysome - transcriptome and translatome of arabidopsis wt seeds according to dormancy - Identification of transcripts that are differentially abundant (transcriptome) and transcripts that are addressed to translation (translatome) in imbibed Arabidopsis seeds in relation with dormancy. During imbibition of seeds (16h and 24h in darkness at 25°C, dormant and non-dormant seeds), transcriptome analysis is done on total RNA and translatome analysis on polysomal RNA. - At harvest seeds are dormant. They stay dormant if they are stored at -20°C (D) and become non-dormant (ND) if they are stored 3 weeks at +20°C. Arabidopsis dormant seeds do not germinate at 25°C in darkness while non-dormant seeds do. Total RNA and polysomal RNA (polysomal fractions purified on sucrose gradients) were extracted from imbibed seeds for 16h or 24h at 25°C in darkness (3 biological replicates). Transcriptome and translatome are compared for Dormant vs Non-Dormant for 16h and 24 imbibition. In silico comparison will allow to compare transcriptome and translatome for each point and type of seeds and to compare the time points (16 vs 24h) for each type of sample. 12 dye-swap - time course
Project description:Production of morphologically and physiologically variable seeds is an important strategy that helps plants to survive in unpredictable natural conditions. However, the model plant Arabidopsis thaliana and most agronomically essential crops yield visually homogenous seeds. Using automated phenotype analysis, we observed that in Arabidopsis small seeds tend to have higher primary and secondary dormancy levels when compared to large ones. Transcriptomic analysis revealed distinct gene expression profiles between large and small seeds. Large seeds had higher expression of translation-related genes implicated in germination competence. In contrast, small seeds showed elevated expression of many positive regulators of dormancy, including a key regulator of this process – the DOG1 gene. Differences in DOG1 expression were associated with differential production of its alternative cleavage and polyadenylation isoforms where in small seeds proximal poly(A) site is selected resulting in a short mRNA isoform. Furthermore, single-seed RNA-seq analysis demonstrated that large seeds resemble DOG1 knockout mutant seeds. Finally, on the single seed level, the expression of genes affected by seed size was correlated with the expression of genes positioning seeds on the path towards germination. Our results demonstrate an unexpected link between seed size and dormancy phenotypes in a species producing highly homogenous seed pools, suggesting that the correlation between seed morphology and physiology is more widespread than initially assumed.
Project description:au14-10_wd40 - effet of light on translatome of arabidopsis seeds during germination - Does light regulates germination via polysome association ? - At harvest seeds are dormant.They stay dormant if stored at -20°C.A.Th dormant seeds dont germinate at 25°C in darkness.Total RNA and polysomal RNA (polysomal fractions purified on sucrose gradients)were extracted from imbibed seeds for 20h at 22°C in darkness and light(3 biological replicates). Transcriptome and translatome are compared for light vs dark for 20h of imbibition. In silico comparison will allow to compare transcriptome and translatome for each type of sample.
Project description:Seeds establish dormancy for survival under severe conditions and break it for renascence under suitable ones. Here We identify a fate switch constituted by MKK3-MPK7 and ERF4 responsible for the transition of seeds state from dormancy to germination. We show that the MKK3-MPK7 module is activated by dormancy-breaking factors, affects and relies on the expression of some EXPAs to control seed dormancy. Furthermore, we identify a direct downstream substrate of this module, ERF4, which can suppress the expression of these EXPAs by directly binding to the GCC box in their exon region. The activated MKK3-MPK7 module phosphorylates ERF4 and leads to its rapid degradation, thereby releasing its inhibitory effect on the expression of these EXPAs. Our work identifies a signaling chain integrated by protein phosphorylation, degradation, and gene transcription, dependent on which the germination promoters within the embryonic nucleus are sensing and activated by the germination signals from the ambient conditions.
Project description:The role of on-CG methylation in seed development and dormancy remains unknown. There are four genes in charge of non-CG methylation in Arabidopsis: drm1, drm2, cmt2 and cmt3. The majority of non-CG methylation in vegetative tissues, leaf, is gone in homozygous ddcc mutant line (Hume et al., 2014). To uncover the possible role of non-CG DNA methylation in seed development and dormancy, we characterized the transcriptome of ddcc mutant in Arabidopsis post-mature green seeds using Illumina sequencing. Meanwhile, post-mature green seeds from wild type were used as control.
Project description:affy_tour_2012-02 - Identification of transcripts that are addressed to traduction in imbibed seeds in relation with dormancy: comparison of the translatome in Dormant versus Non-Dormant seeds -- At harvest seeds are dormant. They stay dormant if they are stored at -20°C (D) and become non-dormant (ND) if they are stored 2 months at +20°C. Polysomal fractions were purified on sucrose gradients from sunflower axis isolated from dormant and non-dormant seeds imbibed at 10°C during 3h, 15h or 24h. - These fractions allow to identify the transcripts addressed to translation (translatome) during the seed imbibition process (3, 15 and 24h) - The translatome of 2 types of seeds are compared: Dormant vs Non-Dormant at the 3 time points. 18 arrays - SUNFLOWER; time course,treated vs untreated comparison