Hsp60 gene as a reliable target for taxonomical identification and discrimination of Leuconostoc species of dairy origin

Abstract

The taxonomic characterisation of Leuconostoc species is still controversial and the methods applied including cultivation, phenotypic/biochemical and non–specific molecular methods (RAPD, PFGE, RFLP, MALDI–TOF MS and sequencing of the gene coding for 16S rRNA), could lead to misidentifications. Sequencing of 16S rRNA gene is still the most applied, although several closely–related species are not always properly differentiated. In this work, a phylogenetic tree constructed by the alignment of a fragment from hsp60 gene of 71 Leuconostoc strains of dairy origin (Ln. mesenteroides, Ln. pseudomesenteroides, Ln. lactis and Ln. citreum) was analysed and compared with that obtained with 16S rRNA sequences. The phylogenetic tree resulted from hsp60 sequences showed greater discrimination, even at the intra–species level, compared with that obtained with 16S rRNA fragments. These results demonstrated that this target sequence could be considered an excellent molecular tool for the identification of Leuconostoc species of dairy importance.