Caleb Pereira

Two light-pink coloured, gram-negative bacterial strains MS613^T and MS785^T were isolated from the waters of saline springs located near Lake Winnipegosis, Manitoba, Canada. The presence of bacteriochlorophyll a incorporated into reaction centres and light-harvesting I complexes, along with no anaerobic or photoautotrophic growth, supports classification as aerobic anoxygenic phototrophs. Similarity based on 16S rRNA identified Meridianimarinicoccus zhengii (98.65%), M. roseus (97.70%), and M. aquatilis (94.98%) as the closest relatives to MS613^T. For MS785^T, they are chemolithoautotroph Roseovarius autotrophicus (97.94%), heterotroph R. nitratireducens (96.58%), and aerobic anoxygenic phototroph R. tolerans (95.92%). Its proximity to these physiologically distinct species is captured by the presence of anoxygenic photosynthesis alongside encoding all Calvin cycle genes, despite not growing autotrophically. The designation of both as new species is supported by differences in their photosynthetic capability, salt tolerance, colony colour, and cell shape compared to closest relatives. Additionally, each strain had low average amino acid identity (Roseobacteraceae. Thus, we propose that strains MS613^T (=NCIMB 15650^T =DSM 122955^T) and MS785^T (=NCIMB 15651^T =DSM 122954^T) be classified as new species with the names Meridianimarinicoccus lucivorans sp. nov. and Roseovarius manitobensis sp. nov.

A pink colored, rod-shaped, prosthecate, Gram-negative bacterial strain MS644^T was discovered in saline spring water near Lake Winnipegosis, Manitoba, Canada. It produces bacteriochlorophyll a, which is incorporated into its reaction center and light harvesting I complex. Alongside no anaerobic or photoautotrophic growth, these features support its designation as an aerobic anoxygenic phototroph (AAP). Unlike most AAP, the photosynthetic apparatus is produced in significantly greater amounts compared to carotenoids. Sequence of the 16S rRNA gene identified relatedness to Glycocaulis albus (96.19%), Glycocaulis alkaliphilus (96.12%) and Glycocaulis abyssi (96.07%). The DNA G + C content was 66.01 mol %. Differences in salt tolerance and photosynthesis capability, alongside low average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization compared to other Maricauaceae, support the designation of the strain as a representative of a new genus. Therefore, we propose that strain MS644^T (=NCIMB 15625^T = DSM 121292^T) be classified as the type species of a new genus Apolloniradiicaulis in Maricaulaceae with the name A. salifontis gen. nov., sp. nov.