Bhattacharjee Ananda S, Schulz Frederik, Woyke Tanja, Orcutt Beth N, Martínez Martínez Joaquín
Bigelow Laboratory for Ocean Sciences, 60 Bigelow Drive, East Boothbay, ME, USA.
Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA.
ISME Commun. 2023 Feb 3;3(1):10. doi: 10.1038/s43705-022-00210-8.
The oceanic igneous crust is a vast reservoir for microbial life, dominated by diverse and active bacteria, archaea, and fungi. Archaeal and bacterial viruses were previously detected in oceanic crustal fluids at the Juan de Fuca Ridge (JdFR). Here we report the discovery of two eukaryotic Nucleocytoviricota genomes from the same crustal fluids by sorting and sequencing single virions. Both genomes have a tRNA gene with an intron (20 bps) at the canonical position between nucleotide 37 and 38, a common feature in eukaryotic and archaeal tRNA genes with short introns (<100 bps), and fungal genes acquired through horizontal gene transfer (HGT) events. The dominance of Ascomycota fungi as the main eukaryotes in crustal fluids and the evidence for HGT point to these fungi as the putative hosts, making these the first putative fungi-Nucleocytoviricota specific association. Our study suggests active host-viral dynamics for the only eukaryotic group found in the subsurface oceanic crust and raises important questions about the impact of viral infection on the productivity and biogeochemical cycling in this ecosystem.
大洋火成岩地壳是微生物生命的巨大储存库，主要由多样且活跃的细菌、古菌和真菌组成。此前在胡安德富卡海岭（JdFR）的大洋地壳流体中检测到了古菌和细菌病毒。在此，我们报告通过对单个病毒粒子进行分选和测序，从同一地壳流体中发现了两个真核核质巨DNA病毒科基因组。这两个基因组都有一个tRNA基因，在核苷酸37和38之间的标准位置有一个内含子（20个碱基对），这是具有短内含子（<100个碱基对）的真核和古菌tRNA基因的共同特征，以及通过水平基因转移（HGT）事件获得的真菌基因。子囊菌纲真菌作为地壳流体中主要的真核生物占主导地位，以及水平基因转移的证据表明这些真菌是推定的宿主，这使得这些成为首个推定的真菌 - 核质巨DNA病毒科特异性关联。我们的研究表明，在大洋地壳次表层发现的唯一真核生物群体存在活跃的宿主 - 病毒动态，并引发了关于病毒感染对该生态系统生产力和生物地球化学循环影响的重要问题。
