Project description:Mangrove plants are the demonstrated woody plants in tropical and subtropical coastal area with great ecological and economic importance. However, due to the extreme global climate change and increased human activities, mangroves is suffering a dramatic declining worldwide. Lumnitzera littorea (Jack) Voigt is one of the most endangered mangrove species in China. A comprehensive understanding on its resistance mechanisms to low ambient temperature help us to better conserve and restore L. littorea. In the current study, we performed comparative transcriptome analysis to investigate the genome-wide changes of gene expression profile in L. littorea under chilling stress (8°C day/5°C night) over normal condition (25°C day/23°C night). The low temperature suppressed fatty acid elongation and protein phosphorylation in L. littorea, while induced calcium ion binding process and signaling transduction, suggesting an activation of cold-stress sensing and signaling in L. littorea. Combining our analysis with our previous physiological assays, we showed a substantial photoinhibition occurring in the seedlings of L. littorea with the decrease of ambient temperature, and the synthesis of photosystem II reaction center protein D1 and peroxidase-involved scavenging of reactive oxygen species (ROS) were enhanced accordingly to combat the adverse impacts. Finally, we highlighted the biological significance of post-transcriptional regulation, including RNA binding and surveillance, in coping with cold stress in L. littorea. Collectively, our findings provide a global view to the resistance mechanisms of chilling stress in L. littorea, and valuable genetic resources to assist the protection and restoration of L. littorea.
Project description:Analyses of new genomic, transcriptomic or proteomic data commonly result in trashing many unidentified data escaping the ‘canonical’ DNA-RNA-protein scheme. Testing systematic exchanges of nucleotides over long stretches produces inversed RNA pieces (here named “swinger” RNA) differing from their template DNA. These may explain some trashed data. Here analyses of genomic, transcriptomic and proteomic data of the pathogenic Tropheryma whipplei according to canonical genomic, transcriptomic and translational 'rules' resulted in trashing 58.9% of DNA, 37.7% RNA and about 85% of mass spectra (corresponding to peptides). In the trash, we found numerous DNA/RNA fragments compatible with “swinger” polymerization. Genomic sequences covered by «swinger» DNA and RNA are 3X more frequent than expected by chance and explained 12.4 and 20.8% of the rejected DNA and RNA sequences, respectively. As for peptides, several match with “swinger” RNAs, including some chimera, translated from both regular, and «swinger» transcripts, notably for ribosomal RNAs. Congruence of DNA, RNA and peptides resulting from the same swinging process suggest that systematic nucleotide exchanges increase coding potential, and may add to evolutionary diversification of bacterial populations.