Diversity and ecology of and biomineralization by magnetotactic bacteria

Abstract

Magnetotactic bacteria (MTB) biomineralize intracellular, membrane-bounded crystals of magnetite (Fe O ) and/or greigite (Fe S ) called magnetosomes. MTB play important roles in the geochemical cycling of iron, sulfur, nitrogen and carbon. Significantly, they also represent an intriguing model system not just for the study of microbial biomineralization but also for magnetoreception, prokaryotic organelle formation and microbial biogeography. Here we review current knowledge on the ecology of and biomineralization by MTB, with an emphasis on more recent reports of unexpected ecological and phylogenetic findings regarding MTB. In this study, we conducted a search of public metagenomic databases and identified six novel magnetosome gene cluster-containing genomic fragments affiliated with the Deltaproteobacteria and Gammaproteobacteria classes of the Proteobacteria phylum, the Nitrospirae phylum and the Planctomycetes phylum from the deep subseafloor, marine oxygen minimum zone, groundwater biofilm and estuary sediment, thereby extending our knowledge on the diversity and distribution of MTB as well deriving important information as to their ecophysiology. We point out that the increasing availability of sequence data will facilitate researchers to systematically explore the ecology and biomineralization of MTB even further.

Magnetosome magnetite biomineralization in a flagellated protist: evidence for an early evolutionary origin for magnetoreception in eukaryotes

“…Representatives of this group are present in a number of phyla including several classes of the Proteobacteria (Sakaguchi et al ., ; Lefèvre et al ., ; Morillo et al ., ; Taoka et al ., ; Abreu et al ., ), the Nitrospirae (Lefèvre et al ., ; Lin et al ., ) and the candidate phylum Omnitrophica (Kolinko et al ., , ). Culture‐independent methods and single‐cell genome analysis indicate that the diversity and phylogenetic distribution of magnetotactic organisms are underestimated (Kolinko et al ., ; Rinke et al ., ) and may extend to other phylogenetic groups including the phyla Latescibacteria and Planctomycetes (Lin and Pan, ; Lin et al ., ; Lin et al ., ) or maybe even other domains of life (Torres de Araujo et al ., ).…”

Genomic study of a novel magnetotacticAlphaproteobacteriauncovers the multiple ancestry of magnetotaxis

“…Previous biodiversity studies revealed the intriguing polyphyletism of magnetic biomineralization within the bacteria domain (Lin et al, 2018). Most of the MTB described so far belong to three classes of Proteobacteria, and some are affiliated to the Nitrospirae and Omnitrophica phyla Lin et al, 2017a). Recent metagenomic data suggested that some bacteria within the Latescibacteria and Planctomycetes phyla could also biomineralize (Lin et al, 2018).…”

“…QH-2 whose region harbouring the magnetosome genes contains few or no mobile elements and present a high stability within the genome (Lefèvre et al, 2011;Ji et al, 2014). Because different strains may support different evolutionary scenarios, it is difficult to arbitrate between vertical and horizontal inheritance, which feeds a permanent debate (Lefèvre et al, 2013a;Lin et al, 2017a).…”

Culture‐independent characterization of a novel magnetotactic member affiliated to the Beta class of the Proteobacteria phylum from an acidic lagoon

“…MTB signature genes in metagenomic sequences obtained from Sakinaw Lake (Canada), a lake where the pH varies from 5.7 to 6.5 and the temperature ranges from 8 to 19 C (Perry, 1990), strongly indicate the possibility of a novel greigite-producing MTB belonging to the candidate phylum 'Latescibacteria' (formerly WS3) (Lin and Pan, 2015) although an MTB of this type was not physically observed from the lake. Recently, a partial greigite-type magnetosome gene cluster has been identified in a draft genome from a bacterium affiliated to Planctomycetes phylum obtained from the sediment of the White Oak River, North Carolina (Lin et al, 2017).…”

“…These strains grow optimally at pH 9.0-9.5, but not at pH 8.0 (Lefèvre et al, 2011). Different morphotypes of MTB have also been found in saline-alkaline lakes in Inner Mongolia, China (Lin et al, 2017). An uncultured moderately thermophilic MTB from the Nitrospirae phylum was discovered in hot spring sediments collected from Great Boiling Springs, Nevada (Lefèvre et al, 2010).…”