Identification of novel species of marine magnetotactic bacteria affiliated with Nitrospirae phylum

Xin‐xin Qian (1, 2) , J Liu (2, 3) , Nicolas Menguy (4, 2) , Jinhua Li (5, 2) , François Alberto (1, 2) , Zhaojie Teng (3) , Tian Xiao (2, 3) , Wenyan Zhang (2, 3) , Long‐fei Wu (1, 2)

1 LCB - Laboratoire de chimie bactérienne
2 LIA-MagMC - International Associated Laboratory of Evolution and Development of Magnetotactic Multicellular Organisms
3 KLMEES - CAS Key Laboratory of Marine Ecology and Environmental Science
4 IMPMC - Institut de minéralogie, de physique des matériaux et de cosmochimie
5 Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China.

Magnetotactic bacteria (MTB) are a group of Gram‐negative bacteria characterized by synthesizing magnetosomes and swimming along geomagnetic field lines. Phylogenetically, they belong to different taxonomic lineages including Proteobacteria, Nitrospirae, Omnitrophica, Latescibacteria and Planctomycetes phyla on the phylogenetic tree. To date, six Nitrospirae MTB phylotypes have been identified from freshwater or low‐salinity environments and described in the literature. Here, we report the identification of two Nitrospirae MTB phylotypes collected, for the first time, from the marine environment. Both have a spherical morphology with a cell size of ~ 5 μM and similar motility but are different colours (black‐brown and ivory‐white) under the optic microscope. They synthesized bullet‐shaped iron‐oxide magnetosomes that were arranged in multiple bundles of chains. Moreover, the cytoplasm of the black‐brown Nitrospirae MTB contained sulphur inclusions that conferred on cells a rough, granular appearance. Phylogenetic analysis based on their 16S rRNA gene sequences revealed that they are two novel species and cluster with the previously reported MTB affiliated with the phylum Nitrospirae, thus extending the distribution of Nitrospirae MTB from freshwater to the marine environment.

Domaines: Sciences du Vivant [q-bio]

Xin‐xin Qian, J Liu, Nicolas Menguy, Jinhua Li, François Alberto, et al.. Identification of novel species of marine magnetotactic bacteria affiliated with Nitrospirae phylum. Environmental Microbiology Reports, 2019, 11 (3), pp.330-337. ⟨10.1111/1758-2229.12755⟩. ⟨hal-02333904⟩