Effects of illumination on nirS denitrifying and anammox bacteria in the rhizosphere of submerged macrophytes

• Published in: The Science of the total environment Vol. 760; p. 143420
• Main Authors: Xiao, Yang, Yin, Xingjia, Chen, Lijuan, Wang, Jing, Wang, Yuchun, Liu, Guanglong, Hua, Yumei, Wan, Xiaoqiong, Xiao, Naidong, Zhao, Jianwei, Zhu, Duanwei
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.03.2021
• Subjects: Anammox bacteria; Bacteria - genetics; Lighting; nirS denitrifying bacteria; Nitrogen; Oxidation-Reduction; Phylogeny; Potamogetonaceae; Rhizosphere; RNA, Ribosomal, 16S; Shading treatment; Submerged macrophyte; Rhizosphere; Submerged macrophyte; nirS denitrifying bacteria; Shading treatment; Anammox bacteria
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.143420

Visibility in lakes can decrease due to increases in the amounts of suspended solids and algae, which inhibits the growth of submerged macrophytes. However, the understanding about whether illumination reduction affects the nitrogen-cycling microorganisms in the rhizosphere of submerged macrophytes, is limited. The abundance and biodiversity of nirS denitrifying and anammox bacteria in the rhizosphere of Potamogeton crispus were studied under 0% (natural light), 20%, 40%, and 60% shading treatments. The abundance of the nirS gene was highest under 60% shading treatment, while the anammox 16S rRNA gene was highest under 40% shading treatment. Moreover, the abundance of the two genes were lower under natural light than under shading conditions during most sampling periods. The quantitative ratio of the two gene (anammox 16S rRNA to nirS gene) abundance fluctuated wildly with the distance away from the roots, under natural light and 20% shading treatment. However, the ratio varied relatively little under 40% and 60% shading treatments. The diversity of nirS denitrifying bacteria was high in the rhizosphere, while the diversity of anammox bacteria was low, and Candidatus Brocadia fulgida was dominant. This study revealed that illumination reduction not only facilitated the growth of nirS denitrifying and anammox bacteria in the rhizosphere, but also weakened the competition between the two bacteria. [Display omitted] •Shading increased the abundance of nirS and anammox 16S rRNA genes in rhizosphere.•Shading changed the interspecific relationship of denitrifying and anammox bacteria.•The diversity of nirS denitrifying bacteria was high.•The diversity of anammox bacteria was low.