Project description:Wheat seed germination directly affects wheat yield and quality. The wheat grains mainly include embryo and endosperm, and both play important roles in seed germination, seedling survival and subsequent vegetative growth. ABA can positively regulate dormancy induction and then negatively regulates seed germination at low concentrations. H2O2 treatment with low concentration can promote seed germination of cereal plants. Although various transcriptomics and proteomics approaches have been used to investigate the seed germination mechanisms and response to various abiotic stresses in different plant species, an integrative transcriptome analysis of wheat embryo and endosperm response to ABA and H2O2 stresses has not reported so far. We used the elite Chinese bread wheat cultivar Zhenmai 9023 as material and performed the first comparative transcriptome microarray analysis between embryo and endosperm response to ABA and H2O2 treatments during seed germination using the GeneChip® Wheat Genome Array Wheat seed germination includes a great amount of regulated genes which belong to many functional groups. ABA/H2O2 can repress/promote seed germination through coordinated regulating related genes expression. Our results provide new insights into the transcriptional regulation mechanisms of embryo and endosperm response to ABA and H2O2 treatments during seed germination
Project description:Wheat seed germination directly affects wheat yield and quality. The wheat grains mainly include embryo and endosperm, and both play important roles in seed germination, seedling survival and subsequent vegetative growth. ABA can positively regulate dormancy induction and then negatively regulates seed germination at low concentrations. H2O2 treatment with low concentration can promote seed germination of cereal plants. Although various transcriptomics and proteomics approaches have been used to investigate the seed germination mechanisms and response to various abiotic stresses in different plant species, an integrative transcriptome analysis of wheat embryo and endosperm response to ABA and H2O2 stresses has not reported so far. We used the elite Chinese bread wheat cultivar Zhenmai 9023 as material and performed the first comparative transcriptome microarray analysis between embryo and endosperm response to ABA and H2O2 treatments during seed germination using the GeneChip® Wheat Genome Array Wheat seed germination includes a great amount of regulated genes which belong to many functional groups. ABA/H2O2 can repress/promote seed germination through coordinated regulating related genes expression. Our results provide new insights into the transcriptional regulation mechanisms of embryo and endosperm response to ABA and H2O2 treatments during seed germination The six groups including embryo and endosperm response to pure water (CK), ABA and H2O2 were havested respectively, which were CK_embryo (CKem), CK_endosperm (CKe), ABA_embryo (ABAem), ABA_endosperm (ABAe), H2O2_embryo (H2O2em), H2O2_endosperm (H2O2e). Three independent experiments were performed for each group.
Project description:Arabidopsis seed germination is coordinated with the strong induction of metabolic pathways required for the mobilisation and utilization of seed storage reserves. These are essential to support the seedling before the establishment of photoauxotrophic growth. The activity of genes encoding enzymes required for lipid mobilisation is regulated largely at the level of transcription, but our knowledge of how this regulation occurs is extremely limited. After germination the rate of lipid reserve mobilisation is determined by the carbohydrate status of the seedling and by the osmotic potential of the growth substrate. The plant response to both of these requires the action of the hormone abscisic acid (ABA). We have shown that this regulation is tissue specific (Penfield et al., 2004 Plant Cell 16, 2705-2718), and that although lipid breakdown in the embryo is inhibited by ABA, lipid breakdown in the endosperm tissues is not. Furthermore, in many species the action of the endosperm is central to the processes controlling seed germination, yet very little is known about gene expression in this tissue, or of the function of the endosperm in mature Arabidopsis seeds. Mature Arabidopsis seeds can be dissected into embryo and endosperm/seed coat fractions, with the latter fraction containing RNA only from the endosperm as the seed coat cells undergo programmed cell death during the latter stages of seed development. In this experiment we divide seeds into embryo and endosperm tissues and transcript profile both shortly after germination, or when germination and lipid reserve mobilisation are inhibited by ABA or by the gibberellin biosynthesis inhibitor paclobutrazol. In this way we can discover the endosperm transcriptome and uncover candidate regulators of lipid mobilisation by searching for genes showing differential expression between embryo and endosperm before and after ABA treatment. Experimenter name = Steven Penfield Experimenter phone = 01904 328759 Experimenter fax = 01904 328762 Experimenter department = Department of Biology Experimenter institute = Centre for Novel Agricultural Products Experimenter address = University of York Experimenter address = PO BOX 373 Experimenter address = York Experimenter zip/postal_code = YO10 5YW Experimenter country = UK Keywords: organism_part_comparison_design
Project description:In Arabidopsis mature seeds, the onset of the embryo-to-seedling transition is nonautonomously controlled, being blocked by endospermic abscisic acid (ABA) release under unfavorable conditions. Mature embryos lack an impermeable cuticle, unlike seedlings, consistent with their endospermic ABA uptake capability. Seedling cuticle formation occurs after germination rather than during embryogenesis. Mature endosperm removal prevents seedling cuticle formation and seed reconstitution by endosperm grafting onto embryos shows that the endosperm promotes seedling cuticle development. Grafting different endosperm and embryo mutant combinations, together with biochemical, microscopy and mass spectrometry approaches, reveals that endospermic release of Tyrosyl Sulfate Transferase (TPST)-sulfated CIF2 and PSY1 peptides promotes seedling cuticle development. Endosperm-deprived embryos produced nonviable seedlings bearing numerous developmental defects, in a manner unrelated to embryo nourishment, all restored by exogenously provided endosperm. Hence, seedling establishment is nonautonomous, requiring the mature endosperm.
Project description:Arabidopsis seed germination is coordinated with the strong induction of metabolic pathways required for the mobilisation and utilization of seed storage reserves. These are essential to support the seedling before the establishment of photoauxotrophic growth. The activity of genes encoding enzymes required for lipid mobilisation is regulated largely at the level of transcription, but our knowledge of how this regulation occurs is extremely limited. After germination the rate of lipid reserve mobilisation is determined by the carbohydrate status of the seedling and by the osmotic potential of the growth substrate. The plant response to both of these requires the action of the hormone abscisic acid (ABA). We have shown that this regulation is tissue specific (Penfield et al., 2004 Plant Cell 16, 2705-2718), and that although lipid breakdown in the embryo is inhibited by ABA, lipid breakdown in the endosperm tissues is not. Furthermore, in many species the action of the endosperm is central to the processes controlling seed germination, yet very little is known about gene expression in this tissue, or of the function of the endosperm in mature Arabidopsis seeds. Mature Arabidopsis seeds can be dissected into embryo and endosperm/seed coat fractions, with the latter fraction containing RNA only from the endosperm as the seed coat cells undergo programmed cell death during the latter stages of seed development. In this experiment we divide seeds into embryo and endosperm tissues and transcript profile both shortly after germination, or when germination and lipid reserve mobilisation are inhibited by ABA or by the gibberellin biosynthesis inhibitor paclobutrazol. In this way we can discover the endosperm transcriptome and uncover candidate regulators of lipid mobilisation by searching for genes showing differential expression between embryo and endosperm before and after ABA treatment. Experimenter name = Steven Penfield; Experimenter phone = 01904 328759; Experimenter fax = 01904 328762; Experimenter department = Department of Biology; Experimenter institute = Centre for Novel Agricultural Products; Experimenter address = University of York; Experimenter address = PO BOX 373; Experimenter address = York; Experimenter zip/postal_code = YO10 5YW; Experimenter country = UK Experiment Overall Design: 18 samples were used in this experiment
Project description:In this study, we performed the first dynamic proteome analysis of wheat seed germination using a two-dimensional differential gel electrophoresis (2D-DIGE)-based proteomic approach. A total of 166 differentially expressed protein (DEP) spots representing 73 unique proteins were identified.
Project description:affy_rice_2011_03 - affy_compartimentation_rice_albumen_embryon - During germination, the rice seed goes from a dry quiescent state to an active metabolism. As with all cereals, the rice seed is highly differentiated between the embryo (that will give rise to the future plantlet) and the endosperm (that contains the seed storage compounds and that will degenerate). The molecular mechanisms operating in the rice seed embryo have begun to be described. Yet, very few studies have focused specifically on the endosperm during the germination process. In particular, the endosperm is mostly addressed with regards to its storage proteins but we have detected a large protein diversity by two-dimensional electrophoresis. Similarly, the endosperm is rich in total RNA which suggest that gene expression coming from seed maturation could play a role during the germination process. In this context, we want to compare the transcriptome of the embryo and the endosperm during rice seed germination. -We germinate rice seeds of the first sequenced rice cultivar i.e. Nipponbare during 0, 4, 8, 12, 16 and 24h of imbibition in sterile distilled water. Germination occurs under constant air bubbling, in the dark at 30°C. These rice seeds are then manually dissected into embryo and endosperm fractions. -The embryo-derived samples are abbreviated in “E” while the endosperm samples are abbreviated “A”. The germination time-point is indicated after the letter (e.g. E8 for embryo samples harvested after 8 hours of germination). Finally, the biological repetition number is indicated before the letter and the time digit (e.g. 1-E8 for an embryo sample from the first repetition at 8 hours of imbibition).
Project description:The endosperm is a nutritive tissue supporting embryo growth in flowering plants. Most commonly, the endosperm initially develops as a coenocyte (multinucleate cell) and then cellularizes. This process of cellularization is frequently disrupted in hybrid seeds generated by crosses between different flowering plant species or plants that differ in ploidy, resulting in embryo arrest and seed lethality. The reason for embryo arrest upon cellularization failure remains unclear. In this study, we show that triploid Arabidopsis thaliana embryos surrounded by uncellularized endosperm mount an osmotic stress response that is connected to increased levels of abscisic acid (ABA) and enhanced ABA responses. Impairing ABA biosynthesis and signalling aggravated triploid seed abortion, while increasing endogenous ABA levels as well as the exogenous application of ABA induced endosperm cellularization and suppressed embryo growth arrest. Taking these results together, we propose that endosperm cellularization is required to establish dehydration tolerance in the developing embryo, ensuring its survival during seed maturation.
Project description:The phytohormone gibberellic acid (GA) is well known to promote seed germination in plants. One of its functions is to stimulate the production of hydrolytic enzymes in the aleurone and their secretion to the adjacent endosperm. The storage in the endosperm is thus degraded by these hydrolases into small molecules, which are utilized as nutrients for embryo growth to establish the young seedling. ABA in contrast plays antagonistic role to GA to keep seed in dormancy. Cereal aleurone has been established as a model system to investigate giberrellin (GA) and abscisic acid (ABA) responses. Using Barley 1 GeneChip, we examined the mRNA accumulation of over 22 000 genes in barley aleurone treated with GA, ABA, GA plus ABA, and sln1 mutant.