Project description:As the only surviving lineages of jawless fishes, hagfishes and lampreys provide a critical window into early vertebrate evolution. Here, we investigate the complex history, timing, and functional role of genome-wide duplications in vertebrates in the light of a chromosome-scale genome of the brown hagfish Eptatretus atami. Using robust chromosome-scale (paralogon-based) phylogenetic methods, we confirm the monophyly of cyclostomes, document an auto-tetraploidization (1RV) that predated the origin of crown group vertebrates ~517 Mya, and establish the timing of subsequent independent duplications in the gnathostome and cyclostome lineages. Some 1RV gene duplications can be linked to key vertebrate innovations, suggesting that this early genomewide event contributed to the emergence of pan-vertebrate features such as neural crest. The hagfish karyotype is derived by numerous fusions relative to the ancestral cyclostome arrangement preserved by lampreys. These genomic changes were accompanied by the loss of genes essential for organ systems (eyes, osteoclast) that are absent in hagfish, accounting in part for the simplification of the hagfish body plan; other gene family expansions account for hagfishes’ capacity to produce slime. Finally, we characterise programmed DNA elimination in somatic cells of hagfish, identifying protein-coding and repetitive elements that are deleted during development. As in lampreys, the elimination of these genes provides a mechanism for resolving genetic conflict between soma and germline by repressing germline/pluripotency functions. Reconstruction of the early genomic history of vertebrates provides a framework for further exploration of vertebrate novelties.
Project description:Experiment with 2 conditions: - Contactless : A. glutinosa alone in nitrogen-free culture medium during 2 days (reference condition). - Indirect : A. glutinosa in nitrogen-free culture medium containing the Frankia bacterium confined in a dialysis tube during 2 days.
Project description:Experiment with 2 conditions: - BAP-PCM : A. glutinosa alone in nitrogen-free culture medium plus frankialess culture medium during 2 days (reference condition). - CN BAP-PCM : A. glutinosa in nitrogen-free culture medium with Frankia culture supernatant during 2 days.
Project description:In this study, roots of Rehmannia glutinosa were used as experimental material, and three tuber roots of Rehmannia glutinosa in extension stage (I), expansion stage (E) and mature stage (M) were selected as samples, The iTRAQ quantitative proteomic technology combined with two-dimensional liquid chromatography and tandem mass spectrometry (2D-LC-MSMS) technology was used to construct the root tuber proteome database of Rehmannia glutinosa, the genes related to the growth and development of Rehmannia glutinosa root tuber were found.
Project description:Alnus glutinosa belongs to a family of angiosperms called actinorhizal plants because they can develop nitrogen-fixing nodules in association with the soil bacteria Frankia. The aim of this transcriptomic study was to get a global view of the plant symbiotic genetic program and to identify new key plant genes that control nodulation during symbiosis in A. glutinosa. Symbiosis between A. glutinosa and Frankia was obtained after inoculation of young plant with a concentrated culture of the bacteria. Inoculation was performed in a medium depleted in nitrogen which favors the induction of nitrogen fixing symbiosis. For this study we considered two stages of symbiosis: - an early stage where inoculated roots were harvested 7 days after inoculation with the bacteria and compared to two controls (non-inoculated roots grown with or without nitrogen and harvested at the same time) - a late stage where nodules (nitrogen-fixing specific organs) were harvested 21 days after inoculation and compared to non-inoculated roots harvested on the day of inoculation (which is our reference time 0d). Three biological replicates were used for each condition.