Microbial community of nitrogen cycle‐related genes in aquatic plant rhizospheres of Lake Liangzi in winter

Abstract

This study investigated the community structure of ammonia‐oxidizing bacteria /archaea (AOB and AOA), as well as the effects of four aquatic plants (namely Ceratophyllum demersum , Hydrilla verticillata , Potamogeton crispus , and Nymphaea tetragona ) rhizospheres on the abundance of AOB amoA , AOA amoA , anammox 16S rRNA, nirK , and nirS in Lake Liangzi, China. Phylogenetic analysis revealed that most AOB groups were Nitrosospira and Nitrosomonas , in which Nitrosospira was dominant. The AOA amoA were affiliated with two branches of classical sequences which belonging to Thaumarchaeota : water/sediments branch and soil/sediments branch. The abundance of AOA amoA in the rhizospheres of aquatic plants were higher than in the non‐rhizosphere ( p < 0.05), indicating that aquatic plants may promote the growth of AOA. However, the anammox 16S rRNA showed the opposite trend relative to AOA amoA ( p < 0.05). Redundancy analysis (RDA) showed that the differences in abundance of AOB, AOA, anammox bacteria, and denitrifying bacteria are very likely related to the different contents of ammonia nitrogen (NH 4 + ‐N), pH and dissolved oxygen (DO) and thus to the rhizosphere states of aquatic plants.