Background Viral-encoded auxiliary metabolic genes (AMGs) are important toolkits for modulating their hosts’ metabolisms and the microbial-driven biogeochemical cycles. Although the functions of AMGs have been extensively reported in numerous environments, we still know little about the drivers that shape the viral community-wide AMG compositions in natural ecosystems. Exploring the drivers of viral community-wide AMG compositions is critical for a deeper understanding of the complex interplays among viruses, hosts, and the environments. Results Here, we investigated the impact of viral lifestyles (i.e., lytic and lysogenic), habitats (i.e., water, particle, and sediment), and prokaryotic hosts on viral AMG profiles by utilizing metagenomic and metatranscriptomic techniques. We found that viral lifestyles were the most important drivers, followed by habitats and host identities. Specifically, irrespective of what habitats viruses came from, lytic viruses exhibited greater AMG diversity and tended to encode AMGs for chaperone biosynthesis, signaling proteins, and lipid metabolism, which could boost progeny reproduction, whereas temperate viruses were apt to encode AMGs for host survivability. Moreover, the lytic and temperate viral communities tended to mediate the microbial-driven biogeochemical cycles, especially nitrogen metabolism, in different manners via AMGs. When focusing on each lifestyle, we further found clear dissimilarity in AMG compositions between water and sediment, as well the divergent AMGs encoded by viruses infecting different host orders. Conclusions Overall, our study provides a first systematic characterization of the drivers of viral community-wide AMG compositions and further expands our knowledge of the distinct interactions of lytic and temperate viruses with their prokaryotic hosts from an AMG perspective, which is critical for understanding virus-host-environment interactions in natural conditions.

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The long-term overexploitation of groundwater leads to serious land subsidence and threatens the safety of Beijing-Tianjin-Hebei (BTH). In this paper, an interferometric point target analysis (IPTA) with small baseline subset InSAR (SBAS-InSAR) technique was used to derive the land subsidence in a typical BTH area from 2012 to 2018 with 126 Radarsat-2 and 184 Sentinel-1 images. The analysis reveals that the average subsidence rate reached 118 mm/year from 2012 to 2018. Eleven subsidence features were identified: Shangzhuang, Beijing Airport, Jinzhan and Heizhuanghu in Beijing, Guangyang and Shengfang in Langfang, Wangqingtuo in Tianjin, Dongguang in Cangzhou, Jingxian and Zaoqiang in Hengshui and Julu in Xingtai. Comparing the different types of land use in subsidence feature areas, the results show that when the land-use type is relatively more complex and superimposed with residential, industrial and agricultural land, the land subsidence is relatively more significant. Moreover, the land subsidence development patterns are different in the BTH areas because of the different methods adopted for their water resource development and utilization, with an imbalance in their economic development levels. Finally, we found that the subsidence changes are consistent with groundwater level changes and there is a lag period between land subsidence and groundwater level changes of approximately two months in Beijing Airport, Jinzhan, Jingxian and Zaoqiang, of three months in Shangzhuang, Heizhuanghu, Guangyang, Wangqingtuo and Dongguang and of four months in Shengfang.

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1. Microbial biogeography has predominantly been studied through a taxonomic lens. However, functional properties of microbial communities are often decoupled from their taxonomic compositions, emphasizing the need to study the biogeography of microbial functional genes directly.2. Here, using the Pearl River Estuary (PRE) sediments as a study system, we characterized the biogeographical patterns of the diversities and abundances of key microbial nitrogen-cycling genes using metagenomic techniques.3. We found that functional genes involved in denitrification and dissimilatory nitrate reduction to ammonium pathways were more diverse and abundant than genes involved in other processes (i.e. nitrogen fixation, nitrification, assimilatory nitrite reduction). The diversities and abundances of certain nitrogen-cycling genes were, to some extent, spatially decoupled. Specifically, the diversities of narG, napA, nirK and nrfA were greater adjacent to the river outlet, whereas the abundances of narG, napA and norB were greater in the downstream of the PRE. These spatial variations were mainly driven by water depth, C/N and NH + 4 . 4. Moreover, nitrogen-cycling genes involved in the same pathways (e.g. denitrification) showed no consistent responses to environmental changes and the main taxa involved in different nitrogen-cycling steps were diverse, providing important clues for explaining why the abundance of single functional gene often seems not to be a reliable proxy for the specific process rate. Overall, our results demonstrate that studying the biogeography of microbial functional genes can help expand our knowledge of the nitrogen cycle from a biogeographical perspective.