Regulation of bacterial nitrogen cycle of aquatic plants rhizosphere in the ecological floating bed system for aquaculture tailwater treatment
QU Jiangqi, LIU Qing, ZHANG Qingjing*, YANG Haochen, ZHAO Meng, ZHU Hua
1.Beijing Key Laboratory of fishery Biotechnology, Fisheries Science Institute, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100068, China; 2.College of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China
Abstract: In order to explore the influence mechanism of 250 m2 floating bed aquatic plants on nitrogen cycle of water bodies by rhizosphere bacteria in the aquaculture tailwater treatment, the differences in the bacterial composition and functional genes related to nitrogen cycling were monthly investigated in front, center, and rear in the aquatic plant Iriswilsonii C.H.Wright floating beds from May to August 2020 by 16S rRNA gene amplicon sequencing and metagenomic sequencing technology. Results showed that Proteobacteria, Firmicutes, Patescibacteria, and Bacteroidota were found to be the dominant phyla in the rhizosphere of Iriswilsonii C.H.Wright roots during the experiment period. At genus level, 10 core functional microorganisms played an important role in the key process of nitrogen migration and transformation in aquaculture tailwater. There was higher microbial diversity and more active nitrogen metabolism activity, primarily in metabolic pathways or functions such as carbon metabolism, ABC transport protein, bacterial two component system and Quorum sensing, in the aquatic plant rhizosphere than those in the floating bed water bodies (P<0.05). Moreover, the relative abundance of rhizosphere nitrogen fixation function genes (nifH, nifD and nifK), nitrification function gene (hao), denitrification function genes (nirS, norB and nosZ), dissimilatory/assimilated nitrate reduction genes (napA, nrfA, nirB and nasA) and their key enzymes in the nitrogen cycle were significantly increased (P<0.05). The rhizosphere microbes of the aquatic plants had stronger nitrogen turnover capacity than that in the surrounding water environment, and microbial denitrification and dissimilatory nitrate reduction process were the main denitrification pathways of the rhizosphere effect of the ecological floating bed aquatic plants.
曲疆奇, 刘青, 张清靖, 杨浩辰, 赵萌, 朱华. 养殖尾水浮床处理系统水生植物根际细菌的氮循环作用机制[J]. 大连海洋大学学报, 2023, 38(1): 12-21.
QU Jiangqi, LIU Qing, ZHANG Qingjing, YANG Haochen, ZHAO Meng, ZHU Hua. Regulation of bacterial nitrogen cycle of aquatic plants rhizosphere in the ecological floating bed system for aquaculture tailwater treatment. Journal of Dalian Ocean University, 2023, 38(1): 12-21.
2023, Vol. 38 
