Diversity of Aerobic Anoxygenic Phototrophs and Rhodopsin-Containing Bacteria in the Surface Microlayer, Water Column and Epilithic Biofilms of Lake Baikal

• Main Authors: Agnia Dmitrievna Galachyants, Andrey Yurjevich Krasnopeev, Galina Vladimirovna Podlesnaya, Sergey Anatoljevich Potapov, Elena Viktorovna Sukhanova, Irina Vasiljevna Tikhonova, Ekaterina Andreevna Zimens, Marsel Rasimovich Kabilov, Natalia Albertovna Zhuchenko, Anna Sergeevna Gorshkova, Maria Yurjevna Suslova, Olga Ivanovna Belykh
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Microorganisms
• Subjects: aerobic anoxygenic phototrophs; rhodopsin-containing bacteria; neuston; plankton; epilithon; Lake Baikal
• Online Access: https://www.mdpi.com/2076-2607/9/4/842

The diversity of aerobic anoxygenic phototrophs (AAPs) and rhodopsin-containing bacteria in the surface microlayer, water column, and epilithic biofilms of Lake Baikal was studied for the first time, employing <i>pufM</i> and rhodopsin genes, and compared to 16S rRNA diversity. We detected <i>pufM</i>-containing Alphaproteobacteria (orders Rhodobacterales, Rhizobiales, Rhodospirillales, and Sphingomonadales), Betaproteobacteria (order Burkholderiales), Gemmatimonadetes, and Planctomycetes. Rhodobacterales dominated all the studied biotopes. The diversity of rhodopsin-containing bacteria in neuston and plankton of Lake Baikal was comparable to other studied water bodies. Bacteroidetes along with Proteobacteria were the prevailing phyla, and Verrucomicrobia and Planctomycetes were also detected. The number of rhodopsin sequences unclassified to the phylum level was rather high: 29% in the water microbiomes and 22% in the epilithon. Diversity of rhodopsin-containing bacteria in epilithic biofilms was comparable with that in neuston and plankton at the phyla level. Unweighted pair group method with arithmetic mean (UPGMA) and non-metric multidimensional scaling (NMDS) analysis indicated a distinct discrepancy between epilithon and microbial communities of water (including neuston and plankton) in the 16S rRNA, <i>pufM</i> and rhodopsin genes.