Project description:Complete submergence represses photosynthesis and aerobic respiration causing rapid mortality in most terrestrial plants, but some species have evolved traits allowing them to survive prolonged flooding. Here, we studied the response to submergence of two species and their F1 hybrid in the genus Rorippa, which is related to the model Arabidopsis. We showed that these species have high tolerance to complete, deep submergence, but R. sylvestris survived longer than R. amphibia and the F1 hybrid. While the former restricted growth upon submergence, the latter two genotypes showed induced stem and petiole elongation and had higher aerenchyma contents, indicative of a low oxygen escape strategy. Arabidopsis GeneChip microarrays were used for whole-genome transcript profiling of roots of young plants exposed to air or a 24-h submergence treatment, using a probe mask based on hybridisation of genomic DNA of both species to the arrays. The induction by the submergence treatment of genes involved in glycolysis and fermentation and repression of many energy consuming pathways was similar to the response to low oxygen of Arabidopsis and rice. Notably, sucrose synthases, glycolysis and fermentation genes were more strongly induced in the less tolerant R. amphibia than in R. sylvestris, which might indicate faster carbohydrate consumption of the former, while some genes involved in hydrogen peroxide scavenging were strongly and specifically induced in the latter. F1 hybrids showed a generally weaker response to submergence and an additive mode of gene action, which did not change by the submergence treatment. Experiment Overall Design: We used replicated clones of Rorippa amphibia, Rorippa sylvestris and their F1 hybrid. Plants were grown on sand in pots for three weeks, completely submerged in rain water for 24 h, or kept in air as a control. Three biological controls were collected per genotype, each consisting of a pool of three individuals. Roots were separated from the shoots, quickly rinsed and immediately frozen and used for RNA extraction and hybridization to Arabidopsis Ath1 GeneChips. Genomic DNA of Rorippa amphibia and Rorippa sylvestris was also hybridized to the GeneChips in order to filter out badly performing probes due to sequence divergences from Arabidopsis.
Project description:Complete submergence represses photosynthesis and aerobic respiration causing rapid mortality in most terrestrial plants, but some species have evolved traits allowing them to survive prolonged flooding. Here, we studied the response to submergence of two species and their F1 hybrid in the genus Rorippa, which is related to the model Arabidopsis. We showed that these species have high tolerance to complete, deep submergence, but R. sylvestris survived longer than R. amphibia and the F1 hybrid. While the former restricted growth upon submergence, the latter two genotypes showed induced stem and petiole elongation and had higher aerenchyma contents, indicative of a low oxygen escape strategy. Arabidopsis GeneChip microarrays were used for whole-genome transcript profiling of roots of young plants exposed to air or a 24-h submergence treatment, using a probe mask based on hybridisation of genomic DNA of both species to the arrays. The induction by the submergence treatment of genes involved in glycolysis and fermentation and repression of many energy consuming pathways was similar to the response to low oxygen of Arabidopsis and rice. Notably, sucrose synthases, glycolysis and fermentation genes were more strongly induced in the less tolerant R. amphibia than in R. sylvestris, which might indicate faster carbohydrate consumption of the former, while some genes involved in hydrogen peroxide scavenging were strongly and specifically induced in the latter. F1 hybrids showed a generally weaker response to submergence and an additive mode of gene action, which did not change by the submergence treatment. Keywords: stress response and a comparison of genotypes
Project description:In genomes of modern fish and amphibia α- and β- globin genes are grouped at a single locus that may resemble the ancestral one and is syntenic to α-globin locus of modern warm-blooded vertebrates. In Danio rerio, the major locus of α/β globin genes comprises two subclusters, one of them harboring genes expressed in adult and the other – genes expressed in embryonic and larval erythrocytes. The results of our previous study suggested that the adult subcluster of this locus has evolved into α-globin gene domain of vertebrate animals. Here we studied how adult and embryo-larval genes of Danio rerio major globin gene locus are repressed in fibroblasts. The results obtained suggest that that at least some of the globin genes present within the adult subcluster are repressed by Polycomb similarly to human α-globin genes. Furthermore, within two α/β gene pairs repression of α-type and β-type genes appears to be mediated by different mechanisms as increasing the level of histone acetylation can activate transcription of only β-type genes.