Detection and Diversity of the Nitrite Oxidoreductase Alpha Subunit (nxrA) Gene of Nitrospina in Marine Sediments

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• 作者：Sundas Rani ; Hyeon-Woo Koh ; Sung-Keun Rhee ; Hirotsugu Fujitani…
• 关键词：Marine sediment ; Pyrosequencing ; nxrA ; Nitrospina ; Nitrite ; oxidizing bacteria
• 刊名：Microbial Ecology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：73
• 期：1
• 页码：111-122
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Microbiology; Ecology; Microbial Ecology; Geoecology/Natural Processes; Nature Conservation; Water Quality/Water Pollution;
• 出版者：Springer US
• ISSN：1432-184X
• 卷排序：73

文摘

Nitrite-oxidizing bacteria (NOB) are chemolithoautotrophs that catalyze the oxidation of nitrite to nitrate, which is the second step of aerobic nitrification. In marine ecosystems, Nitrospina is assumed to be a major contributor to nitrification. To date, two strains of Nitrospina have been isolated from marine environments. Despite their ecological relevance, their ecophysiology and environmental distribution are understudied owing to fastidious cultivation techniques and the lack of a sufficient functional gene marker. To estimate the abundance, diversity, and distribution of Nitrospina in various marine sediments, we used nxrA, which encodes the alpha subunit of nitrite oxidoreductase, as a functional and phylogenetic marker. We observed that Nitrospina diversity in polar sediments was significantly lower than that of non-polar samples. Moreover, nxrA-like sequences revealed an unexpected diversity of Nitrospina, with approximately 41,000 different sequences based on a 95% similarity cutoff from six marine sediments. We detected nxrA gene copy numbers of up to 3.57 × 104 per gram of marine sediment sample. The results of this study provide insight into the distribution and diversity of Nitrospina, which is fundamentally important for understanding their contribution to the nitrogen cycle in marine sediments.