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Summary Bryophytes harbour microbiomes, including diverse communities of fungi. The molecular mechanisms by which perennial mosses interact with these fungal partners along their senescence gradients are unknown, yet this is an ideal system to study variation in gene expression associated with trophic state transitions. We investigated differentially expressed genes of fungal communities and their hostDicranum scopariumacross its naturally occurring senescence gradient using a metatranscriptomic approach. Higher activity of fungal nutrient‐related (carbon, nitrogen, phosphorus and sulfur) transporters and Carbohydrate‐Active enZyme (CAZy) genes was detected toward the bottom, partially decomposed, layer of the moss. The most prominent variation in the expression levels of fungal nutrient transporters was from inorganic nitrogen‐related transporters, whereas the breakdown of organonitrogens was detected as the most enriched gene ontology term for the hostD. scoparium, for those transcripts having higher expression in the partially decomposed layer. The abundance of bacterial rRNA transcripts suggested that more living members ofCyanobacteriaare associated with the photosynthetic layer ofD. scoparium, while members ofRhizobialesare detected throughout the gametophytes. Plant genes for specific fungal–plant communication, including defense responses, were differentially expressed, suggesting that different genetic pathways are involved in plant‐microbe crosstalk in photosynthetic tissues compared to partially decomposed tissues.
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Transcriptional patterns of Emiliania huxleyi in the North Pacific Subtropical Gyre reveal the daily rhythms of its metabolic potential
Summary Emiliania huxleyiis a calcifying haptophyte, contributing to both the organic and inorganic marine carbon cycles. In marine ecosystems, light is a major driver of phytoplankton physiology and ultimately carbon flow through the ecosystem. Here, we analysed a Lagrangian time‐series of metatranscriptomes collected in the North Pacific Subtropical Gyre (NPSG) to examine howin situpopulations ofE.huxleyimodulate gene expression over day–night transitions. ManyE.huxleyicontigs had a diel expression pattern, with 61% of contigs clustering into modules with statistically significant diel periodicity. Contigs involved in processes that build up energy stores, like carbon fixation and lipid synthesis, peaked around dawn. In contrast, contigs involved in processes that released energy stores, like respiration and lipid degradation, peaked mid‐day and towards dusk. These patterns suggest an orchestrated cycle of building, then consuming energy stores inE.huxleyipopulations in the NPSG. Selected contigs related to the cell cycle also exhibited significant diel periodicity consistent with phased modulations of division observed in culture. Overall, these patterns of gene expression suggest a daily metabolic cascade that could contribute to both organic and inorganic carbon flow in this nutrient depleted ecosystem.
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- Award ID(s):
- 1742716
- PAR ID:
- 10459839
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Environmental Microbiology
- Volume:
- 22
- Issue:
- 1
- ISSN:
- 1462-2912
- Format(s):
- Medium: X Size: p. 381-396
- Size(s):
- p. 381-396
- Sponsoring Org:
- National Science Foundation
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