Nitrogen Fixation Activity and Genome Analysis of a Moderately Haloalkaliphilic Anoxygenic Phototrophic Bacterium Rhodovulum tesquicola

Anastasia V Komova; Elizaveta D Bakhmutova; Anna O Izotova; Evelina S Kochetova; Stepan V Toshchakov; Zorigto B Namsaraev; Maxim V Golichenkov; Aleksei A Korzhenkov

doi:10.3390/microorganisms10081615

Nitrogen Fixation Activity and Genome Analysis of a Moderately Haloalkaliphilic Anoxygenic Phototrophic Bacterium Rhodovulum tesquicola

Microorganisms. 2022 Aug 9;10(8):1615. doi: 10.3390/microorganisms10081615.

Authors

Anastasia V Komova¹, Elizaveta D Bakhmutova¹, Anna O Izotova¹, Evelina S Kochetova¹, Stepan V Toshchakov¹, Zorigto B Namsaraev¹, Maxim V Golichenkov^{2

3}, Aleksei A Korzhenkov¹

Affiliations

¹ Kurchatov Centre for Genome Research, NRC Kurchatov Institute, 123098 Moscow, Russia.
² Soil Biology Department, Soil Science Faculty, Moscow State University, 119991 Moscow, Russia.
³ Department of Biology, Faculty of Pediatrics, Pirogov Russian National Research Medical University, 117997 Moscow, Russia.

Abstract

The genome of the moderately haloalkaliphilic diazotrophic anoxygenic phototrophic bacterium Rhodovulum tesquicola A-36s^T isolated from an alkaline lake was analyzed and compared to the genomes of the closest species Rhodovulum steppense A-20s^T and Rhodovulum strictum DSM 11289^T. The genomic features of three organisms are quite similar, reflecting their ecological and physiological role of facultative photoheterotrophs. Nevertheless, the nitrogenase activity of the pure cultures of the studied bacteria differed significantly: the highest rate (4066 nmoles C₂H₂/mg of dry weight per hour) was demonstrated by Rhodovulum strictum while the rates in Rhodovulum tesquicola and Rhodovulum steppense were an order of magnitude lower (278 and 523 nmoles C₂H₂/mg of dry weight per hour, respectively). This difference can be attributed to the presence of an additional nitrogenase operon found exclusively in R. strictum and to the structural variation in nitrogenase operon in R. tesquicola.

Keywords: Rhodovulum tesquicola; alkaliphiles; anoxygenic phototrophs; diazotroph; genome sequence; halophiles; nitrogen fixation.

Grants and funding

This research was funded by Ministry of Science and Higher Education of Russian Federation (Agreement No. 075-15-2019-1659 with Kurchatov Center of Genome Research) and Russian Foundation for Basic Research (grant # 20-04-60190).