Project description:The combination of robust physiological models with “omics” studies holds promise for the discovery of genes and pathways linked to how organisms deal with drying. Here we used a transcriptomics approach in combination with an in vivo physiological model of re-establishment of desiccation tolerance (DT) in Arabidopsis thaliana seeds. We show that the incubation of desiccation-sensitive (DS) germinated Arabidopsis seeds in a polyethylene glycol (PEG) solution re-induces the mechanisms necessary for expression of DT. Based on a SNP-tile array gene expression profile, our data indicates that the re-establishment of DT, in this system, is related to a programmed reversion from a metabolic active to a quiescent state similar to prior to germination. Our findings show that transcripts of germinated seeds after the PEG treatment are dominated by those encoding LEA, seed storage and dormancy-related proteins. On the other hand, a massive repression of genes belonging to many other classes such as photosynthesis, cell wall modification and energy metabolism occurs in parallel. Furthermore, comparison with a similar system for Medicago truncatula reveals a significant overlap between the two transcriptomes. Such overlap may highlight core mechanisms and key regulators of the trait DT. Taking into account the availability of the many genetic and molecular resources for Arabidopsis, the described system may prove useful for unraveling DT in higher plants. Desiccation-sensitive seeds vs. desiccation-tolerant seeds in the same developmental stage in triplicate.
Project description:Transcriptomic study of the impact of osmopriming on rape seeds (Brassica napus L.; cv 'Libomir') during priming process and after germination. The assays were replicated twice on two independent priming and germination experiments. Seeds were osmoprimed in PEG solution (-1.2 MPa osmotic potential) during 7 days, dried to initial moisture content and then germinated for 7 hours on water. The analysis during different phases of priming procedure (soaking and drying), after whole osmopriming process and germination were done. 10 samples, four condition experiment; non dried primed seeds (Pnd) vs. dry unprimed seeds (UPd) (PEG soaking), non dried primed seeds (Pnd) vs dry primed seeds (Pd) (drying after soaking), dry primed seeds (Pd) vs. dry unprimed seeds (UPd) (full osmopriming process), primed seeds imbibed on water (P7h) vs unprimed seeds imbibed on water (UP7h) (germination after osmopriming). Biological replicates: 2 replicates for comparison PEG soaking, drying after soaking, full osmopriming process and germination after osmopriming.
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. Barley aleurone tissues were separated from half-seed without embryo. Three independent RNA samples for each treatment including the control without any hormone were extracted and hybridized onto Affymetrix microarrays. We also did microarray in three replications for sln1 mutant aleurone without hormone treatment.