An internal recycling mechanism between ammonia/ammonium and nitrate driven by ammonia-oxidizing archaea and bacteria (AOA, AOB, and Comammox) and DNRA on Angkor sandstone monuments
An internal recycling mechanism between ammonia/ammonium and nitrate driven by ammonia-oxidizing archaea and bacteria (AOA, AOB, and Comammox) and DNRA on Angkor sandstone monuments
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DOI：
10.1016/j.ibiod.2021.105328
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发表时间：
2021-10-19
影响因子：
4.8
通讯作者：
Gu, Ji-Dong
中科院分区：
文献类型：
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作者：
Ding, Xinghua;Lan, Wensheng;Gu, Ji-Dong
柬埔寨的古代吴哥窟砂岩古迹因砂岩在热带气候下的生物退化而闻名。本研究通过基于DNA的宏基因组学分析、基于RNA的功能基因逆转录（RT）-qPCR定量和N-15同位素分析，研究了吴哥窟、吴哥窟巴戎寺和柏威夏三个重要古迹石居微生物组中的氨氧化细菌（AOB和Comammox）和古菌（AOA）。我们的宏基因组数据显示，这三个古迹丰富的微生物组和丰富的微生物氮转化反应的氨氧化和亚硝酸盐氧化，Comammox和异化硝酸盐还原为铵（DNRA），这些结果支持氨/铵和硝酸盐之间的内部循环机制AOA，AOB，Comammox和DNRA的石碑，以支持微生物群落。虽然从这些宏基因组中检索到广泛的AOB和AOA谱系以及Comammox作为潜在的氨氧化剂，但只有AOA和Comammox最丰富，可能有助于氨氧化的生化过程。在这项研究中，基于RNA的qPCR定量功能基因amoA表明，在这些吴哥砂岩古迹的微生物组中，AOA是比AOB更活跃的氨氧化剂。此外，大量产生AOA和Comammox的亚硝酸盐/硝酸盐促使CO2封存到石头上，而这一过程反过来又得到DNRA的支持，为氨/铵和硝酸盐之间连续发生的进一步循环反应提供底物氨/铵。这一模式进一步支持了高富集的稳定同位素N-15的签名NO3-在砂岩表面生物膜。本研究的结果对于阐明硝态氮累积的内在N循环机制具有重要意义，对于了解石文化遗产的可持续微生物群落和保护管理具有重要意义。
The ancient Angkorian sandstone monuments in Cambodia are well known for biodeterioration of the sandstone under tropic climate. This study examined ammonia oxidizing bacteria (AOB and Comammox) and archaea (AOA) in stone-dwelling microbiome from three important Angkor monuments, namely Angor Wat, Bayon of Angkor Thom, and Preah Vihear, by DNA-based metagenomics analysis, RNA-based functional gene reverse transcriptional (RT)-qPCR quantification, and N-15 isotope analysis. Our metagenomics datasets on these three monuments reveal a rich microbiome and abundant microbial nitrogen transforming reactions of ammonia oxidation and nitrite oxidation, Comammox and dissimilatory nitrate reduction to ammonium (DNRA), and these results support an internal recycling mechanism between ammonia/ammonium and nitrate by AOA, AOB, Comammox and DNRA on the stone monuments to support the microbial community. Though a wide range of AOB and AOA lineages together with Comammox were retrieved from these metagenomes as the potential ammonia-oxidizers, only AOA and Comammox were most abundant, likely to contribute to the biochemical processes of ammonia oxidation. The RNA-based qPCR quantification of the functional gene amoA in this study showed that AOA were the more active ammonia oxidizers over AOB in the microbiome of these Angkor sandstone monuments. In addition, a rich population of nitrite/nitrate producing AOA and Comammox drove the sequestration of CO2 onto the stone and this process was in turn supported by DNRA to provide the substrate ammonia/ammonium for a further cyclic reaction to take place continuously between ammonia/ammonium and nitrate. This model is further supported by the high enrichment of stable isotope N-15 signature of NO3- in sandstone surface biofilms. The findings of this study are insightful for elucidation of nitrate accumulation by an internal N cycling mechanism proposed, and are important for understanding the sustainable microbial community and protection management of stone cultural heritage.