[B-CG07] 岩石生命相互作用とその応用

[BCG07-04] Revealing the population-level structures of prokaryotic communities associated with ferromanganese nodules through 16S rRNA gene amplicon sequencing.

★Invited Papers

*富永 賢人¹、武部 紘明²、村上 知里³、津根 明³、岡村 嵩彦⁴、池上 拓志⁴、大西 庸介⁴、神川 龍馬²、吉田 天士² (1.東京大学　、2.京都大学、3.深海資源開発株式会社、4.株式会社 KANSOテクノス )

キーワード：マンガン団塊、 16S rRNA 遺伝子アンプリコン解析

Despite the potential for exploitation of deep-sea ferromanganese nodules, the mechanisms behind their formation are still poorly understood. Previous studies using amplicon sequencing of 16S rRNA genes have identified various prokaryotic species associated with these nodules, suggesting their involvement in the formation process. However, recent advancements in amplicon sequence variant (ASV)-level monitoring have revealed that closely related prokaryotic populations within the same taxonomic unit can exhibit distinct ecological properties. This implies that conventional species-level monitoring may have overlooked nodule-specific populations when multiple distinct populations of the same species were present in the surrounding environments. In this study, we aimed to investigate the diversity of prokaryotic communities in nodules and their surrounding environments in the Clarion-Clipperton Zone of Japanese-licensed areas. We employed 16S rRNA gene amplicon sequencing with ASV-level resolution during three cruises from 2017 to 2019. Our results showed that the composition and diversity of prokaryotic communities varied significantly depending on the habitat type, including nodules, nodule-surface mud, sediment, bottom water, and water column. Most ASVs (~80%) were specific to a particular habitat. Through linear discriminant effect size analysis, we identified 178 ASVs associated with nodules and 41 ASVs associated with nodule-surface mud. Notably, certain ASVs, such as those belonging to SAR324 and Woeseia, exhibited high specificity to nodules. These nodule-specific ASVs hold great promise as targets for future investigations into the nodule formation process.