Project description:Arctic Mesorhizobium strain N33 was isolated from nodules of the Oxytropis arctobia in Canada’s eastern Arctic. This symbiotic bacterium can grow from 0 to 30°C, is one of the best known cold-adapted rhizobia, and can fix nitrogen at ~10°C. Here, the key molecular mechanisms of cold adaptation were investigated by determining changes in transcript profiles when cells were treated under eight different temperature conditions, including both sustained and transient cold treatments compared with cells grown at room temperature.
Project description:Analysis of gene expression changes of Mesorhizobium alhagi CCNWXJ12-2 under high salt stress. Mesorhizobium alhagi CCNWXJ12-2 is isolated from Alhagi sparsifolia in northwest of China.
Project description:Mesorhizobium metallidurans STM 2683 and Mesorhizobium sp. strain STM 4661 were isolated from nodules of the metallicolous legume Anthyllis vulneraria from distant mining spoils. They tolerate unusually high zinc and cadmium concentrations as compared to other mesorhizobia. This work aims to study the gene expression profiles associated with zinc or cadmium exposure and to identify genes involved in metal tolerance in these two metallicolous Mesorhizobium strains of interest for mine phytostabilization purposes.
Project description:Arctic alpine species experience extended periods of cold and unpredictable conditions during flowering. Thus, often, alpine plants use both sexual and asexual means of reproduction to maximise fitness and ensure reproductive success. We used the arctic alpine perennial Arabis alpina to explore the role of prolonged cold exposure on adventitious rooting. We exposed plants to 4 °C for different durations and scored the presence of adventitious roots on the main stem and axillary branches. Our physiological studies demonstrated the presence of adventitious roots after 21 weeks at 4 °C saturating the effect of cold on this process. Notably, adventitious roots on the main stem developingin specific internodes allowed us to identify the gene regulatory network involved in the formation of adventitious roots in cold using transcriptomics. These data and histological studies indicated that adventitious roots in A. alpina stems initiate during cold exposure and emerge after plants experience growth promoting conditions. While the initiation of adventitious root was not associated with changes of DR5 auxin response and free endogenous auxin level in the stems, the emergence of the adventitious root primordia was. Using the transcriptomic data, we discerned the sequential hormone responses occurring in various stages of adventitious root formation and identified supplementary pathways putatively involved in adventitious root emergence, such as glucosinolate metabolism. Together, our results highlight the role of low temperature during clonal growth in alpine plants and provide insights on the molecular mechanisms involved at distinct stages of adventitious rooting.
Project description:Different populations of the same species survive different environments through local adaptation. Temperature is one of the most important driving forces that could result in local adaptation. Here, we studied the influence of extreme low temperature on the survival of two genetically and geographically distinct populations of the free-living Caenorhabditis briggsae. We found that Caenorhabditis briggsae strains of temperate origin had a cold resistant phenotype, while those originating from a tropical climate had reduced survival after cold treatment. Using this phenotypic difference between geographically diverse populations as a model for how species adapt to their local environment, we then analyzed the transcriptional profiles of two Caenorhabditis briggsae strains of tropical and temperate origin to find genes that are involved in survival after extreme cold. In summary, the response to the extreme low temperature that clearly distinguishes the temperate and tropical Caenorhabditis briggsae strains could serve as an excellent example for studying local adaption of species that show genetic separation associated with their geographical distribution.
Project description:Mesorhizobium metallidurans STM 2683 and Mesorhizobium sp. strain STM 4661 were isolated from nodules of the metallicolous legume Anthyllis vulneraria from distant mining spoils. They tolerate unusually high zinc and cadmium concentrations as compared to other mesorhizobia. This work aims to study the gene expression profiles associated with zinc or cadmium exposure and to identify genes involved in metal tolerance in these two metallicolous Mesorhizobium strains of interest for mine phytostabilization purposes. Mesorhizobium metallidurans STM 2683 and Mesorhizobium sp. strain STM 4661 with three treatments (control, Zn and Cd).
Project description:Analysis of gene expression changes of Mesorhizobium alhagi CCNWXJ12-2 under high salt stress. Mesorhizobium alhagi CCNWXJ12-2 is isolated from Alhagi sparsifolia in northwest of China. Total RNA extracted from Mesorhizobium alhagi CCNWXJ12-2 growing in TY medium containing 0.4 M NaCl and 0 M NaCl.
Project description:Low temperature is one of the major abiotic stresses limiting rice growth and productivity, it is urgent to reveal the genetic and molecular mechanisms of plant responses to low temperature stress and to search for useful genetic resources for improving low-temperature tolerance. the 8 accessions from China Core Collection include 4 cold tolerance accessions, 3 sensitivity accessions and 1 intermediate type accession. We used microarrays to detail variation of the gene expression after cold treatment and screen more cold-response genes in rice.
Project description:We analysed the transcriptomic response by RNAseq of 5 Mesorhizobium strains with different tolerance to the presence of salt (NaCl) in their liquid culture medium (medium used TY- Tryptone Yeast Extract).
