Potential for mercury methylation by Asgard archaea in mangrove sediments

被引：16

作者：

Zhang, Cui-Jing ^{[1
,2
]}

Liu, Yu-Rong ^{[3
]}

Cha, Guihong ^{[4
]}

Liu, Yang ^{[1
,2
]}

Zhou, Xin-Quan ^{[3
]}

Lu, Zhongyi ^{[1
,2
]}

Pan, Jie ^{[1
,2
]}

Cai, Mingwei ^{[1
,2
,5
]}

Li, Meng ^{[1
,2
]}

机构：

[1] Shenzhen Univ, Inst Adv Study, Archaeal Biol Ctr, Shenzhen 518060, Peoples R China

[2] Shenzhen Univ, Inst Adv Study, Shenzhen Key Lab Marine Microbiome Engn, Shenzhen 518060, Peoples R China

[3] Huazhong Agr Univ, State Key Lab Agr Microbiol, Wuhan 430070, Peoples R China

[4] Minist Agr & Rural Affairs, Biogas Inst, Key Lab Dev & Applicat Rural Renewable Energy, Chengdu, Peoples R China

[5] Chem Biol Inst, Shenzhen Bay Lab, Shenzhen, Peoples R China

来源：

ISME JOURNAL | 2023年 / 17卷 / 03期

基金：

中国国家自然科学基金;

关键词：

GEN; NOV; METHYLMERCURY; ANNOTATION; ALIGNMENT; GENOME; TREE; TOOL; BIOACCUMULATION; MICROORGANISMS; ORIGIN;

D O I：

10.1038/s41396-023-01360-w

中图分类号：

Q14 [生态学（生物生态学）];

学科分类号：

071012 ; 0713 ;

摘要：

Methylmercury (MeHg) is a potent neurotoxin that bioaccumulates along food chains. The conversion of MeHg from mercury (Hg) is mediated by a variety of anaerobic microorganisms carrying hgcAB genes. Mangrove sediments are potential hotspots of microbial Hg methylation; however, the microorganisms responsible for Hg methylation are poorly understood. Here, we conducted metagenomic and metatranscriptomic analyses to investigate the diversity and distribution of putative microbial Hg-methylators in mangrove ecosystems. The highest hgcA abundance and expression occurred in surface sediments in Shenzhen, where the highest MeHg concentration was also observed. We reconstructed 157 metagenome-assembled genomes (MAGs) carrying hgcA and identified several putative novel Hg-methylators, including one Asgard archaea (Lokiarchaeota). Further analysis of MAGs revealed that Deltaproteobacteria, Euryarchaeota, Bacteroidetes, Chloroflexi, and Lokiarchaeota were the most abundant and active Hg-methylating groups, implying their crucial role in MeHg production. By screening publicly available MAGs, 104 additional Asgard MAGs carrying hgcA genes were identified from a wide range of coast, marine, permafrost, and lake sediments. Protein homology modelling predicts that Lokiarchaeota HgcAB proteins contained the highly conserved amino acid sequences and folding structures required for Hg methylation. Phylogenetic tree revealed that hgcA genes from Asgard clustered with fused hgcAB genes, indicating a transitional stage of Asgard hgcA genes. Our findings thus suggest that Asgard archaea are potential novel Hg-methylating microorganisms and play an important role in hgcA evolution.

引用

页码：478 / 485

页数：8