Phylogeny, genomics, and symbiosis of Photobacterium

Historical microbiology: revival and phylogenetic analysis of the luminous bacterial cultures of M. W. Beijerinck

Luminous bacteria isolated by Martinus W. Beijerinck were sealed in glass ampoules in 1924 and 1925 and stored under the names Photobacterium phosphoreum and 'Photobacterium splendidum'. To determine if the stored cultures were viable and to assess their evolutionary relationship with currently recognized bacteria, portions of the ampoule contents were inoculated into culture medium. Growth and luminescence were evident after 13 days of incubation, indicating the presence of viable cells after more than 80 years of storage. The Beijerinck strains are apparently the oldest bacterial cultures to be revived from storage. Multi-locus sequence analysis, based on the 16S rRNA, gapA, gyrB, pyrH, recA, luxA, and luxB genes, revealed that the Beijerinck strains are distant from the type strains of P. phosphoreum, ATCC 11040(T), and Vibrio splendidus, ATCC 33125(T), and instead form an evolutionarily distinct clade of Vibrio. Newly isolated strains from coastal seawater in Norway, France, Uruguay, Mexico, and Japan grouped with the Beijerinck strains, indicating a global distribution for this new clade, designated as the beijerinckii clade. Strains of the beijerinckii clade exhibited little sequence variation for the seven genes and approximately 6300 nucleotides examined despite the geographic distances and the more than 80 years separating their isolation. Gram-negative bacteria therefore can survive for many decades in liquid storage, and in nature, they do not necessarily diverge rapidly over time.

Genome sequence of Photobacterium mandapamensis strain svers.1.1, the bioluminescent symbiont of the cardinal fish Siphamia versicolor

Photobacterium mandapamensis is one of three luminous Photobacterium species able to form species-specific bioluminescent symbioses with marine fishes. Here, we present the draft genome sequence of P. mandapamensis strain svers.1.1, the bioluminescent symbiont of the cardinal fish Siphamia versicolor, the first genome of a symbiotic, luminous Photobacterium species to be sequenced. Analysis of the sequence provides insight into differences between P. mandapamensis and other luminous and symbiotic bacteria in genes involved in quorum-sensing regulation of light production and establishment of symbiosis.