Genetic and phenotypic evidence for Streptomyces griseus ecovars isolated from a beach and dune sand system

This study was designed to determine the biogeography of six alkaliphilic Streptomyces strains which had been isolated from four locations within a 60 m transect across a beach and dune sand system. The six strains shared >99% 16S rRNA gene similarities with one another and with representative strains of Streptomyces griseus. Infraspecific diversity amongst the strains was investigated by multilocus sequence typing (MLST) in combination with carbon utilisation phenotypic testing. The results show that each of the strains is genotypically and phenotypically distinct. Furthermore, the MLST and carbon utilisation profiles were congruent thereby providing preliminary evidence which suggests that the observed infraspecific diversity is consistent with ecological selection. The results also demonstrate that infraspecific diversity can be observed over small spatial scales. These findings support the hypothesis that the six isolates are ecovars of Streptomyces griseus. The implications of these findings for prokaryotic biogeography and bioprospecting are discussed.