Sphagnum capillifolium holobiont from a subarctic palsa bog aggravates the potential of nitrous oxide emissions

• Published in: Frontiers in plant science 2022-09, Vol.13, p.974251
• Main Authors: Nie, Yanxia, Lau, Sharon Yu Ling, Tan, Xiangping, Lu, Xiankai, Liu, Suping, Tahvanainen, Teemu, Isoda, Reika, Ye, Qing, Hashidoko, Yasuyuki
• Format: Article
• Language: English
• Subjects: bacteria; N2O emitters; N2O-related genes; permafrost peat; Plant Science; Sphagnum moss
• ISSN: 1664-462X; 1664-462X
• DOI: 10.3389/fpls.2022.974251

Melting permafrost mounds in subarctic palsa mires are thawing under climate warming and have become a substantial source of N O emissions. However, mechanistic insights into the permafrost thaw-induced N O emissions in these unique habitats remain elusive. We demonstrated that N O emission potential in palsa bogs was driven by the bacterial residents of two dominant mosses especially of (SC) in the subarctic palsa bog, which responded to endogenous and exogenous factors such as secondary metabolites, nitrogen and carbon sources, temperature, and pH. SC's high N O emission activity was linked with two classes of distinctive hyperactive N O emitters, including sp. and bacteria, whose hyperactive N O emitting capability was characterized to be dominantly pH-responsive. As the gene-harboring emitter, sp. SC-H2 reached a high level of N O emissions that increased significantly with increasing pH. For emitters lacking the gene, bacterium SC-L1 was more adaptive to natural acidic conditions, and N O emissions also increased with pH. Our study revealed previously unknown hyperactive N O emitters in found in melting palsa mound environments, and provided novel insights into SC-associated N O emissions.