Project description:<p>Salt marshes are highly productive ecosystems where microbial communities drive key</p><p>transformations of organic matter at rates often exceeding those of oceanic and inland</p><p>environments. Viruses are recognised as important drivers and regulators of global</p><p>biogeochemical cycling, yet their diversity, host range, and functional roles in salt</p><p>marsh ecosystems remain largely unresolved. To address these gaps, we investigated</p><p>how viral lysis and host reprogramming can affect microbe-mediated organic matter</p><p>transformations in a salt marsh of the Venice lagoon (Italy). Focusing on tidal creek</p><p>surface sediments, we reconstructed 311 metagenome-assembled genomes (MAGs),</p><p>built corresponding genome-scale metabolic models (GEMs) individually constrained</p><p>with 121 metabolites detected in the sediments, and identified 3,537 viral populations</p><p>(vOTUs) across 10 samples. To assess the impact of viral lysis, we inferred prokaryotic</p><p>hosts for 243 vOTUs and analysed host metabolism through MAG pathway analysis</p><p>and GEM flux modelling across 13 bacterial orders, thus highlighting a negative impact</p><p>on polysaccharide degradation, organic nitrogen mineralisation, and organosulphur</p><p>mineralisation/volatilisation processes. For host metabolic reprogramming, we</p><p>characterised a subset of 50 auxiliary viral genes (AVGs) by mapping them to GEM</p><p>reactions and analysing their stoichiometry, directionality, and pathway context,</p><p>outlining two dominant strategies: resource scavenging through nucleotide-sugar</p><p>biosynthesis, amino acid utilisation, and sulphate assimilation; functional host</p><p>maintenance through cofactor biosynthesis, electron transport, and energy production</p><p>through carbonyl-compound utilisation. Our findings provide a mechanistic view of the</p><p>viral influence on organic matter transformations in salt marsh sediments and confirm</p><p>viruses as key players in salt marsh biogeochemistry.</p>
Project description:Environmental extracts and fractions obtained with passive sampling (HP-20, SMIRC) from Mission Bay, Point Loma, Scripps Pier, Salton Sea (San Diego and Imperial Counties)
2023-10-18 | MSV000093148 | MassIVE
Project description:Prokaryotic biodiversity in Antarctic deep-sea sediments drive
