@article {30979,
	title = {In-situ expressions of comammox Nitrospira along the Yangtze River},
	journal = {Water ResearchWater Research},
	volume = {200},
	year = {2021},
	note = {Times Cited: 1Zheng, Tong/0000-0002-2606-316011879-2448},
	month = {Jul 15},
	abstract = {The recent discovery of comammox Nitrospira as complete nitrifiers has significantly enriched our under-standing on the nitrogen cycle, yet little is known about their metabolic transcripts in natural aquatic ecosystems. Using the genome-centric metatranscriptomics, we provided the first in-situ expression pat-terns of comammox Nitrospira along the Yangtze River. Our study confirmed widespread expressions of comammox Nitrospira, with the highest transcription accounting for 33.3\% and 63.8\% of amoA and nxrAB genes expressed in ammonia-oxidizing prokaryotes (AOPs) and Nitrospira sublineages I/II, respectively. Moreover, comammox two clades differed in nitrification, with clade A acting as the dominator to am-monia oxidation in comammox, and clade B contributing more transcripts to nitrite oxidation than to ammonia oxidation. Compared to canonical Nitrospira, comammox community had lower expressions of ammonia/nitrite transporters and nitrogen assimilatory genes, but far higher expressions in urea trans-port and hydrolysis, facilitating to derivation of ammonia and energy mainly through intracellular ure-olytic metabolism. This suggests no need for \&quot;reciprocal-feeding\&quot; between canonical Nitrospira and AOPs in a natural river. Aerobic mixotrophy of comammox bacteria was suggested by expressions of genes coding for respiratory complexes I-V, oxidative/reductive TCA cycle, oxygen stress defenses, and trans-port/catabolism of simple carbohydrates and low-biosynthetic-cost amino acids. Intriguingly, significant positive correlations among expressions of ammonia monooxygenases, hydroxylamine dehydrogenase and copper-dependent nitrite reductase indicated that comammox Nitrospira had the potential of converting nitrite to nitric oxide accompanied by ammonia oxidation under low-C/N and aerobic conditions, while gene expressions in this pathway were significantly and positively associated with pH. Overall, this study illustrated novel transcriptional characteristics of comammox Nitrospira, and highlighted the necessity of reassessing their contributions to biogeochemical carbon and nitrogen cycling with perspective of in-situ meta-omics as well as culture experiments. (c) 2021 Elsevier Ltd. All rights reserved.},
	isbn = {0043-1354},
	author = {Shufeng Liu and Cai, Hetong and Wang, Jiawen and Haiying Wang and Zheng, Tong and Qian Chen and Ni, Jinren}
}
