Integrated Transcriptome Sequencing (RNA-seq) and Proteomic Studies Reveal Resource Reallocation towards Energy Metabolism and Defense in Skeletonema marinoi in Response to CO(2) Increase

• Published in: Applied and Environmental Microbiology
• Main Authors: Zhang, Mei, Zhen, Yu, Mi, Tiezhu, Lin, Senjie
• Format: Text
• Language: English
• Published: American Society for Microbiology 2021
• Subjects: Physiology; Ocean acidification
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8090871/; http://www.ncbi.nlm.nih.gov/pubmed/33355106; https://doi.org/10.1128/AEM.02614-20

Rising atmospheric CO(2) concentrations are causing ocean acidification (OA) with significant consequences for marine organisms. Because CO(2) is essential for photosynthesis, the effect of elevated CO(2) on phytoplankton is more complex, and the mechanism is poorly understood. Here, we applied transcriptome sequencing (RNA-seq) and iTRAQ proteomics to investigate the impacts of CO(2) increase (from ca. 400 to 1,000 ppm) on the temperate coastal marine diatom Skeletonema marinoi. We identified 32,389 differentially expressed genes and 1,826 differentially expressed proteins from conditions where the CO(2) is elevated, accounting for 48.5% of the total genes and 25.9% of the total proteins we detected, respectively. Elevated partial CO(2) pressure (pCO(2)) significantly inhibited the growth of S. marinoi, and the “omic” data suggested that this might be due to compromised photosynthesis in the chloroplast and raised mitochondrial energy metabolism. Furthermore, many genes/proteins associated with nitrogen metabolism, transcriptional regulation, and translational regulation were markedly upregulated, suggesting enhanced protein synthesis. In addition, S. marinoi exhibited higher capacity of reactive oxygen species production and resistance to oxidative stress. Overall, elevated pCO(2) seems to repress photosynthesis and growth of S. marinoi and, through massive gene expression reconfiguration, induce cells to increase investment in protein synthesis, energy metabolism, and antioxidative stress defense, likely to maintain pH homeostasis and population survival. This survival strategy may deprive this usually dominant diatom in temperate coastal waters of its competitive advantages in acidified environments. IMPORTANCE Rising atmospheric CO(2) concentrations are causing ocean acidification with significant consequences for marine organisms. Chain-forming centric diatoms of Skeletonema is one of the most successful groups of eukaryotic primary producers with widespread geographic distribution. Among the recognized 28 ...