Metagenomic Evidence for Cobamide Producers Driving Prokaryotic Co-occurrence Associations and Potential Function in Wastewater Treatment Plants

Cobamides are required by most organisms but are only produced by specific prokaryotic taxa. These commonly shared cofactors play significant roles in shaping the microbial community and ecosystem function. Wastewater treatment plants (WWTPs) are the world’s most common biotechnological systems; knowledge about sharing of cobamides among microorganisms is predicted to be important to decipher the complex microbial relationships in these systems. Herein, we explored prokaryotic potential cobamide producers in global WWTP systems based on metagenomic analyses. A set of 8253 metagenome-assembled genomes (MAGs) were recovered and 1276 (15.5%) of them were identified as cobamide producers, which could potentially be used for the practical biological manipulation of WWTP systems. Moreover, 8090 of the total recovered MAGs (98.0%) contained at least one enzyme family dependent on cobamides, indicating the sharing of cobamides among microbial members in WWTP systems. Importantly, our results showed that the relative abundance and number of cobamide producers improved the complexity of microbial co-occurrence networks and most nitrogen, sulfur, and phosphorus cycling gene abundances, indicating the significance of cobamides in microbial ecology and their potential function in WWTP systems. These findings enhance the knowledge of cobamide producers and their functions in WWTP systems, which has important implications for improving the efficiency of microbial wastewater treatment processes.钴酰胺（cobamides）为多数生物所必需，但仅由特定原核生物类群合成。这类广泛分布的辅因子在塑造微生物群落结构与生态系统功能方面发挥着关键作用。污水处理厂（wastewater treatment plants, WWTPs）是全球最普及的生物技术系统，解析微生物间的钴酰胺共享机制，被认为对阐明该系统内复杂的微生物互作关系至关重要。本研究基于宏基因组分析，对全球污水处理厂系统中的潜在原核钴酰胺生产者进行了探究。研究共恢复得到8253个宏基因组组装基因组（metagenome-assembled genomes, MAGs），其中1276个（占比15.5%）被鉴定为钴酰胺生产者，这类菌株有望用于污水处理厂系统的实际生物调控。此外，总计恢复的宏基因组组装基因组中有8090个（占比98.0%）携带至少一种依赖钴酰胺的酶家族，这表明污水处理厂系统内的微生物成员间存在钴酰胺共享现象。尤为重要的是，本研究结果显示，钴酰胺生产者的相对丰度与数量提升了微生物共现网络的复杂度，同时多数氮、硫、磷循环相关基因的丰度也随之升高，这印证了钴酰胺在微生物生态学中的重要意义，以及其在污水处理厂系统中的潜在功能。本研究结果加深了人们对污水处理厂系统中钴酰胺生产者及其功能的认知，对提升微生物污水处理工艺的运行效率具有重要指导意义。