Project description:What methylation changes are occurring during seed development largely remains unknown. To uncover the possible role of DNA methylation throughout all of seed development - from fertilization through dormancy and post-germination in soybean, we characterized the methylome of whole seeds representing the differentiation (GLOB and COT stages), maturation (early- [EM], mid- [B1] and late- [AA1] maturation stages), dormancy (DRY stage), and post-germination (seedling) phases of soybean seed development using Illumina sequencing. In addition, we characterized the methylome of the cotyledons of germinated seedling to examine methylation differences before and after germination.
Project description:Purpose: A time-course transcriptome study to identify probable GA-responsive genes in soybean embryonic axes during seed germination. Methods: Seeds were germinated in the presence or absence of 200 µM PBZ. Seeds were germinated in 28°C temperature and 12/12h photoperiod (dark/light) and harvested at 12, 24 and 36 hours after imbibition (HAI). Three biological replicates were performed. Results: Identification of GA-responsive genes during germination in Glycine max.
Project description:Seeds of the legume Castanospermum australe are shed at relatively high moisture contents, and to do not acquire desiccation tolerance during their seed development, they are referred to as 'recalcitrant'. To characterize the regulatory pathways and molecular mechnanisms are occur during seed development and to allow for a comparative analysis with seed development of desiccation-tolerant species, cotyledon and embryonic axes were harvested at different stages of development, arbitrarily defined in terms of seed weight (grams) and color. Transcriptomes of 6 stages were analysed using Nimblegen slides: 2.5g - 4.5g - 7.5g - yellow-green (YG) - green (G) - brown (B) for cotyledons (C) and YG, G and B for emrbyonic axes (A)
Project description:Mycorrhizal fungi colonize orchid seed and induce the germination. This so-called symbiotic germination is a critical developmental process in the lifecycle of all orchids. However, the molecular changes taking place during the orchid seed symbiotic germination still remains largely unknown. To better understand the molecular mechanism of orchid seed germination, we performed comparative transcriptomic and proteomic analysis on Chinese traditional medicinal orchid plants, Dendrobium officinale to explore protein expression change at the different developmental stages between asymbiotic and symbiotic germination and identify the key proteins regulated symbiotic germination of orchid seeds. iTRAQ analysis from 8 samples identified 2256 plant proteins, of which, 308 proteins were differentially expressed across three developmental stages within asymbiotic or symbiotic accession and 229 proteins are differentially expressed in the symbiotic germination compared to asymbiotic germination. 32 proteins are co-upregulated in both proteomic and transcriptomic level for symbiotic germination compared to asymbiotic germination. Our results revealed that symbiotic germination of D. officinale seeds probably shares the common signal pathway with asymbiotic germination during the early germination stage.
Project description:Seeds experience several stress responses from dry to germinated state. To determine the regulators contributing to imbibitional tolerance, dynamic transcriptome analyses were conducted at dry (0 h), imbibed (24 h) and germinated (48 h) stages in japonica Jiucaiqing in this study. Results showed that the differentially expressed genes (DEGs) were pronounced in the early stage (0-24 h) than the late stage (24-48 h); 1,452 transcripts were differentially expressed (648 up-regulated and 804 down-regulated) in the early stage and 625 transcripts (230 up-regulated and 395 down-regulated) in the late stage. Gene ontology and MapMan analyses confirmed that 391 and 164 DEGs at the early and late stage respectively involved in stress responses pathway. These DEGs included the abiotic stress-, hormone-, peroxidases-, signaling-, transcription-, proteolysis- and cell wall-related genes. Nearly all the heat stress-related DEGs, e.g. hsp20 and DnaK family proteins, were down-regulated with seed germination, while the peroxidases- and signaling-related DEGs, e.g. calcium-binding proteins, were up-regulated. Many auxins-, abscisic acid- and ethylene-related DEGs, e.g. 9-cis-epoxycarotenoid dioxygenase, OsFBL16 and OsSAUR33, were involved in stress responses during seed germination. Meanwhile, several transcription factors of bZIP and MYB, ethylene responsive element binding protein family (ERF), and heat stress transcription factor family (HSF) were identified during seed germination. The proteolysis-related DEGs, e.g. ubiquitin-related proteins, were significantly regulated during seed germination. The uniformity between transcriptome data, quantitative trait loci co-localizations and quantitative RT-PCR results confirm the crucial roles of the cell wall-related genes on seed germination. The identified stress-responsive might be useful for the improvement of imbibitional tolerance in rice.
Project description:Desiccation tolerance (DT) is the capacity to withstand total loss of cellular water. This property is acquired during seed filling and lost just after germination. However, in many species, a germinated seed can regain DT under adverse conditions such as osmotic stress. We discovered that the germinated seeds of the abscisic acid insensitive 5 (Mtabi5) mutant of Medicago truncatula lost their ability to re-establish DT during osmotic stress. To characterize the molecular processes that are influenced by MtABI5 during the re-establishment of DT tolerance, a transcriptome analysis was performed on the protruded radicles of germinated Mtabi5 mutants and wilt type before and after an osmotic treatment.
Project description:How epigenetics is involved in the transition from seed maturation to seed germination largely remains elusive. To uncover the possible role of epigenetics in gene expression during the transition from seed maturation to seed germination in soybean, the transcriptome of cotyledons from four stages of soybean seed maturation and germination, including mid-late maturation, late maturation, seed dormancy and seed germination, were profiled by Illumina sequencing. For the genes that are quantitatively regulated at the four stages, two antagonistic epigenetic marks, H3K4me3 and H3K27me3, together with the binding of RNA polymerase II, were investigated at the four stages by chromatin immunoprecipitation (ChIP). For 10 out of 16 genes examined, the relative enrichment of histone modification marks (H3K4me3 and H3K27me3) and RNA polymerase II binding on their promoter regions correlates well with their relative expression levels at four stages, suggesting the involvement of epigenetics in transcriptional regulation. A striking finding is that seed germination-specific genes start to show open chromatin (H3K4me3) during late seed maturation although their transcripts do not accumulate, which is further supported by RNA polymerase II binding. Together, our results provide the first evidence that seed germination genes can be primed for transcription (open chromatin and RNA polymerase II binding) during seed maturation, highlighting that the transition from seed maturation to seed germination starts at late seed maturation stages at both the genetic and epigenetic levels.
Project description:affy_rice_2012_01 - ivt - One of the key questions for future agriculture will be to save agronomical relevant biodiversity. To do so, it is important to select the best crop cultivars that will germinate efficiently (good seed vigor) and for a long period of time (good seed longevity). Surprisingly, while mankind rely heavily on cereals, very few studies have identified genes positively related to cereal seed vigor and longevity. To close this scientific gap, we aimed to identify genes positively involved in rice seed vigor and longevity. We thus used a “controlled deterioration treatment (Tesnier et al., 2002) to mimic natural seed ageing. Seeds are first equilibrated at 25°C and 85% relative hygrometry during three days. Then, during 15 days, three different batch of seeds are either (i) kept at 25°C and 85% RH (control seeds), (ii) placed at 40°C and 85% RH (loss of seed vigor) or (iii) placed at 45°C and 85% RH (loss of germination capacity). Finally, seeds are equilibrated at 25°C and 32% RH during three days. Using this CDT treatment, we obtained rice seeds with contrasted seed vigor or germination capacity. We extracted the total RNA from the embryos and we analysed their transcriptome using the Affymetrix Rice Genome Array.-We applied a Controlled Deterioration Treatment (CDT) to seeds from the reference rice cultivar Nipponbare. First, all seeds are equilibrated at 25°C and 85% relative hygrometry. Then, depending on the treatment, seeds are placed at 25, 40 or 45°C in 85% relative hygrometry before being finally equilibrated at 25°C and 32% relative hygrometry. The germination of the three seed batches was measured during five days with one measure every 8h. Seeds placed at 25°C during the whole experiment were similar to control seeds kept in the fridge and germinated at nearly 100% in 48h. Seeds placed at 40°C during 15 days germinate at 74% but show altered seedling phenotypes (loss of seed vigor). Finally, seeds placed at 45°C do not germinate.
Project description:affy_rice_2012_01 - ovation - One of the key questions for future agriculture will be to save agronomical relevant biodiversity. To do so, it is important to select the best crop cultivars that will germinate efficiently (good seed vigor) and for a long period of time (good seed longevity). Surprisingly, while mankind rely heavily on cereals, very few studies have identified genes positively related to cereal seed vigor and longevity. To close this scientific gap, we aimed to identify genes positively involved in rice seed vigor and longevity. We thus used a “controlled deterioration treatment (Tesnier et al., 2002) to mimic natural seed ageing. Seeds are first equilibrated at 25°C and 85% relative hygrometry during three days. Then, during 15 days, three different batch of seeds are either (i) kept at 25°C and 85% RH (control seeds), (ii) placed at 40°C and 85% RH (loss of seed vigor) or (iii) placed at 45°C and 85% RH (loss of germination capacity). Finally, seeds are equilibrated at 25°C and 32% RH during three days. Using this CDT treatment, we obtained rice seeds with contrasted seed vigor or germination capacity. We extracted the total RNA from the embryos and we analysed their transcriptome using the Affymetrix Rice Genome Array.-We applied a Controlled Deterioration Treatment (CDT) to seeds from the reference rice cultivar Nipponbare. First, all seeds are equilibrated at 25°C and 85% relative hygrometry. Then, depending on the treatment, seeds are placed at 25, 40 or 45°C in 85% relative hygrometry before being finally equilibrated at 25°C and 32% relative hygrometry. The germination of the three seed batches was measured during five days with one measure every 8h. Seeds placed at 25°C during the whole experiment were similar to control seeds kept in the fridge and germinated at nearly 100% in 48h. Seeds placed at 40°C during 15 days germinate at 74% but show altered seedling phenotypes (loss of seed vigor). Finally, seeds placed at 45°C do not germinate.
Project description:Seed germination is characterized by a constant change of gene expression across different time points. These changes are related to specific processes, which eventually determine the onset of seed germination. To get a better understanding on the regulation of gene expression during seed germination, we measured gene expression levels of Arabidopsis thaliana Bay x Sha recombinant inbred lines (RILs) at four important seed germination stages (primary dormant, after-ripened, six-hour after imbibition, and radicle protrusion stage) using. We mapped the eQTL of the gene expression and the result displayed the distinctness of the eQTL landscape for each stage. We found several eQTL hotspots across stages associated with the regulation of expression of a large number of genes. Together, we have revealed that the genetic regulation of gene expression is dynamic along the course of seed germination.