Cyanate and urea are substrates for nitrification by Thaumarchaeota in the marine environment
Cyanate and urea are substrates for nitrification by Thaumarchaeota in the marine environment
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DOI：
10.1038/s41564-018-0316-2
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发表时间：
2019-02-01
影响因子：
28.3
通讯作者：
Bristow, Laura A.
中科院分区：
文献类型：
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作者：
Kitzinger, Katharina;Padilla, Cory C.;Bristow, Laura A.
塔乌姆考古塔藻门的氨氧化古菌是最丰富的海洋微生物(1)。这些生物在海洋中茁壮成长，尽管存在低纳摩尔浓度的铵(2，3)。一些塔乌姆考古塔分离物已被证明利用尿素和氰酸盐作为能量和氮源，通过细胞内转化为铵(4-6)。然而，目前尚不清楚在养殖中观察到的模式是否延伸到海洋塔姆考古塔，也不清楚海洋中的塔姆考古塔是直接利用尿素和氰酸盐，还是依靠共生微生物将这些底物分解为铵。已报告海洋氨氧化群落利用尿素(7-10个)，但没有证据表明海洋氨氧化剂利用氰酸盐。在这里，我们证明了在墨西哥湾，塔乌姆考古塔直接和间接地使用尿素和氰酸盐作为能源和氮源。我们观察到尿素和氰酸盐加成产生亚硝酸盐的速率是实质性的和线性的，即使当铵添加到微摩尔浓度时，这种速率通常也会持续存在。此外，单细胞分析显示，塔乌玛考古菌吸收铵、尿素和氰酸盐衍生的N的速率明显高于大多数其他微生物。然而，在墨西哥湾的古生菌基因组数据中没有检测到氰基酶。因此，我们测试了Maritimus Nitrosopumilus对氰酸盐的利用，该Nitrosopumilus maritimus也缺乏典型的氰酸酶，结果表明氰酸盐被氧化成亚硝酸盐。我们的发现表明，海洋塔乌姆考古塔可以利用尿素和氰酸盐作为能源和氮源。在这些结果的基础上，我们假设尿素和氰酸盐是整个海洋中氨氧化塔姆考古塔的底物。
Ammonia-oxidizing archaea of the phylum Thaumarchaeota are among the most abundant marine microorganisms(1). These organisms thrive in the oceans despite ammonium being present at low nanomolar concentrations(2,3). Some Thaumarchaeota isolates have been shown to utilize urea and cyanate as energy and N sources through intracellular conversion to ammonium(4-6). Yet, it is unclear whether patterns observed in culture extend to marine Thaumarchaeota, and whether Thaumarchaeota in the ocean directly utilize urea and cyanate or rely on co-occurring microorganisms to break these substrates down to ammonium. Urea utilization has been reported for marine ammonia-oxidizing communities(7-10), but no evidence of cyanate utilization exists for marine ammonia oxidizers. Here, we demonstrate that in the Gulf of Mexico, Thaumarchaeota use urea and cyanate both directly and indirectly as energy and N sources. We observed substantial and linear rates of nitrite production from urea and cyanate additions, which often persisted even when ammonium was added to micromolar concentrations. Furthermore, single-cell analysis revealed that the Thaumarchaeota incorporated ammonium-, urea- and cyanate-derived N at significantly higher rates than most other microorganisms. Yet, no cyanases were detected in thaumarchaeal genomic data from the Gulf of Mexico. Therefore, we tested cyanate utilization in Nitrosopumilus maritimus, which also lacks a canonical cyanase, and showed that cyanate was oxidized to nitrite. Our findings demonstrate that marine Thaumarchaeota can use urea and cyanate as both an energy and N source. On the basis of these results, we hypothesize that urea and cyanate are substrates for ammonia-oxidizing Thaumarchaeota throughout the ocean.