Genomic Evidence for the Recycling of Complex Organic Carbon by Novel Thermoplasmatota Clades in Deep-Sea Sediments

• DOI: 10.1128/msystems.00077-22
• Publication Date: 2022-04-18T08:30:10Z
• Authors: Peng-Fei Zheng; Zhanfei Wei; Yingli Zhou; Qingmei Li; Zhao Qi; Xiaoping Diao; Yong Wang
• Keywords: Sink (geography); Carbon sink; Carbon fibers

Thermoplasmatota have been widely reported in a variety of ecosystems, but their distribution and ecological role marine sediments are still elusive. Here, we obtained four draft genomes affiliated with the former RBG-16-68-12 clade, which is now considered new order, "Candidatus Yaplasmales," phylum from South China Sea. The phylogenetic trees based on 16S rRNA genes showed that "Ca. Yaplasmales" archaea composed three clades: A, B, C. Among them, clades A B abundantly distributed (up to 10.86%) anoxic sediment layers (>10-cm depth) six eight cores 1,200- 3,400-m depths. Metabolic pathway reconstructions indicated all capacity for alkane degradation by predicted alkyl-succinate synthase. Clade might be mixotrophic microorganisms identification complete Wood-Ljungdahl putative involved aromatic halogenated organic compounds. Clades C were likely heterotrophic, especially potential spermidine/putrescine compound degradation, as suggested significant negative correlation between concentrations compounds relative abundances clade B. sulfide-quinone oxidoreductase pyrophosphate-energized membrane proton pump encoded serving adaptive strategies energy production. These findings suggest synergistically transform benthic pollutant detrital matter, possibly playing vital terrestrial sedimentary carbon cycle. IMPORTANCE Deep oceans receive large amounts complex anthropogenic pollutants. deep-sea continental slopes serve biggest sink Earth. Particulate carbons proteins accumulate sediment. microbially mediated recycling largely unknown, an important question budget global maintenance ecosystem. In this study, report prevalence 10.86% microbial community) novel order Thermoplasmatota, depths We provide genomic evidence anaerobic alkanes, aliphatic monoaromatic hydrocarbons, Our study identifies key archaeal players sediments, probably critical oceans.