Abdullah Al Mamun, Zhang Dandan, Liu Sirui, Ming Yuzhen, Li Mingyue, Xing Peng, Yu Xiaoli, Niu Mingyang, Wu Kun, Xie Wei, He Zhili, Yan Qingyun
Marine Synthetic Ecology Research Center, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Marine Science, Guangdong Provincial Observation and Research Station for Marine Ranching in Lingdingyang Bay, China-ASEAN Belt and Road Joint Laboratory On Mariculture Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Zhuhai, 519082, China.
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China.
Curr Microbiol. 2024 Dec 22;82(1):53. doi: 10.1007/s00284-024-04032-w.
Denitrifying bacteria, particularly nirK- and nirS-type, are functionally equivalent and could occupy different niches, but their community assembly mechanisms and responses to environmental heterogeneity are poorly understood in eutrophic lakes. In this study, we investigated the community assembly mechanisms of nirK- and nirS-type denitrifying bacteria and clarified their responses to sediments environmental factors in Lake Taihu, China. The quantitative real-time PCR and Illumina HiSeq-based sequencing revealed that the abundance and composition of two types of denitrifying bacterial communities varied among different sites in the sediments of Lake Taihu. The functions of these two types of denitrifying bacteria were assigned to mainly nitrogen cycling along with carbon, oxygen, and sulfur cycling, indicating their diverse ecosystems functions. Neutral community model showed that majority of nirK- and nirS-type denitrifying bacteria were neutrally distributed, while dispersal and selection were the dominant drivers in shaping community assembly of nirK-type bacteria. The community assembly of nirS-type was mainly driven by homogeneous selection. We found complex network interactions between nirK- and nirS-type denitrifying bacteria with other bacterial communities, indicating the importance of other bacterial coexistence for ecosystem functions by denitrifying bacteria in lake sediments. Keystone taxa of other bacteria showed the highest interactions with denitrifying bacteria; further, a strong significant correlation between keystone taxa with environmental factors and sediment enzyme content revealed by Mantel tests. Specially, total phosphorous was the key environmental factor determining the composition and diversity of nirK and nirS-type denitrifying bacteria in lake sediments, whereas NAR, AmoA, and NIR were the key reductase enzymes directly or indirectly affected to them. Our results provide significant insights into understanding the effects of changing nirK- and nirS-type denitrifying bacterial diversities and underlying community assembly mechanisms under changing environmental conditions in eutrophic lake ecosystems.
反硝化细菌，特别是nirK型和nirS型，在功能上是等效的，并且可能占据不同的生态位，但在富营养化湖泊中，它们的群落组装机制以及对环境异质性的响应却鲜为人知。在本研究中，我们调查了nirK型和nirS型反硝化细菌的群落组装机制，并阐明了它们对中国太湖沉积物环境因子的响应。定量实时PCR和基于Illumina HiSeq的测序表明，太湖沉积物不同位点的两种反硝化细菌群落的丰度和组成各不相同。这两种反硝化细菌的功能主要与碳、氧和硫循环一起参与氮循环，表明它们具有多样的生态系统功能。中性群落模型表明，大多数nirK型和nirS型反硝化细菌呈中性分布，而扩散和选择是塑造nirK型细菌群落组装的主要驱动因素。nirS型的群落组装主要由同质选择驱动。我们发现nirK型和nirS型反硝化细菌与其他细菌群落之间存在复杂的网络相互作用，这表明湖泊沉积物中其他细菌的共存对反硝化细菌的生态系统功能具有重要意义。其他细菌的关键类群与反硝化细菌的相互作用最为强烈；此外，Mantel检验显示关键类群与环境因子和沉积物酶含量之间存在很强的显著相关性。特别是，总磷是决定湖泊沉积物中nirK型和nirS型反硝化细菌组成和多样性的关键环境因子，而NAR、AmoA和NIR是直接或间接影响它们的关键还原酶。我们的研究结果为理解富营养化湖泊生态系统中环境条件变化下nirK型和nirS型反硝化细菌多样性变化的影响以及潜在的群落组装机制提供了重要见解。
