Specific quorum sensing molecules of ammonia oxidizers and their role during ammonium metabolism in Zhalong wetland, China

摘要

The primary challenge of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) surviving in wetlands are the rapid and unpredictable environmental changes. To adapt to a fluctuant environment, ammonia oxidizers have to communicate with each other via acyl-homoserine lactones (AHLs). In this study, AOA and AOB in the soil samples taken from Zhalong wetland were incubated. Dynamics of AHLs during the incubation of ammonia oxidizers were measured. Then, the specific AHLs of AOA and AOB were identified, respectively. The results showed that AOA secreted N-butyryl-DL-homoserine lactone (C-4-HSL) and N-octanoyl-L-homoserine lactone (C-8-HSL) to cope with nitrite accumulation, while they secreted N-(3-oxododecanoyl)-DL-homoserine lactone (OXOC12-HSL) to regulate their ammonium metabolism activity. AOB secreted N-hexanoyl-DL-homoserine lactone (C-6-HSL), N-dodecanoyl-L-homoserine lactone (C-12-HSL), N-tetradecanoyl-DL-homoserine lactone (C-14-HSL) and N-(3-oxododecanoyl)-tetradecanoyl-DL-homoserine lactone (OXOC14-HSL) only to enhance the metabolism activity. The dominant AOA belonged to the Nitrososphaera lineage, while the dominant AOB grouped into the Nitrosomonas lineage. The AHLs receptor homologs were identified in both AOA and AOB, which confirmed that AOA and AOB had the QS system. The present work was the first study that elucidated the QS system of AOA and AOB in multidimensional, and confirmed the role of QS system in ammonia oxidizers' metabolism. (C) 2019 Elsevier B.V. All rights reserved.