Metatranscriptomes reveal functional variation in diatom communities from the Antarctic Peninsula

• Published in: The ISME Journal
• Main Authors: Pearson, Gareth A., Lago-Lestón, Asunción, Cánovas, Fernando, Cox, Cymon J., Verret, Frédéric, Lasternas, Sebastien, Duarte, Carlos M., Agustí, Susana, Serrao, Ester Álvares
• Other Authors: Fundação para a Ciência e a Tecnologia (Portugal), Ministerio de Economía y Competitividad (España)
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Nature Publishing Group 2015
• Subjects: Antarctic; Antarctic Peninsula; Bellingshausen Sea; Bransfield Strait; The Antarctic; Weddell; Weddell Sea; Wilkins; Wilkins Ice Shelf; Antarc*; Ice Shelf; Sea ice
• Online Access: http://hdl.handle.net/10261/126061; https://doi.org/10.1038/ismej.2015.40; https://doi.org/10.13039/501100001871; https://doi.org/10.13039/501100003329

© 2015 International Society for Microbial Ecology All rights reserved. Functional genomics of diatom-dominated communities fromthe Antarctic Peninsula was studied using comparative metatranscriptomics. Samples obtained from diatom-rich communities in the Bransfield Strait, the western Weddell Sea and sea ice in the Bellingshausen Sea/Wilkins Ice Shelf yielded more than 500K pyrosequencing reads that were combined to produce a global metatranscriptome assembly. Multi-gene phylogenies recovered three distinct communities, and diatom-assigned contigs further indicated little read-sharing between communities, validating an assembly-based annotation and analysis approach. Although functional analysis recovered a core of abundant shared annotations that were expressed across the three diatom communities, over 40% of annotations (but accounting for <10% of sequences) were community-specific. The two pelagic communities differed in their expression of N-metabolism and acquisition genes, which was almost absent in post-bloom conditions in the Weddell Sea community, while enrichment of transporters for ammonia and urea in Bransfield Strait diatoms suggests a physiological stance towards acquisition of reduced N-sources. The depletion of carbohydrate and energy metabolism pathways in sea ice relative to pelagic communities, together with increased light energy dissipation (via LHCSR proteins), photorespiration, and NO 3 - uptake and utilization all pointed to irradiance stress and/or inorganic carbon limitation within sea ice. Ice-binding proteins and cold-shock transcription factors were also enriched in sea ice diatoms. Surprisingly, the abundance of gene transcripts for the translational machinery tracked decreasing environmental temperature across only a 4 °C range, possibly reflecting constraints on translational efficiency and protein production in cold environments. This work was supported by grants 'SOPA' from the Portuguese Science Foundation (FCT; PTDC/MAR/72630) to GAP and is a contribution to the ATOS ...