Molecular diversity of Leuconostoc mesenteroides and Leuconostoc citreum isolated from traditional French cheeses as revealed by RAPD fingerprinting,16S rDNA sequencing and 16S rDNA fragment amplification

For a long time, the identification of the Leuconostoc species has been lim ited by a lack of accurate biochemical and physiological tests. Here, we us e a combination of RAPD, 16S rDNA sequencing, and 16S rDNA fragment amplifi cation with specific primers to classify different leuconostocs at the spec ies and strain level. We analysed the molecular diversity of a collection o f 221 strains mainly isolated from traditional French cheeses. The majority of the strains were classified as Leuconostoc mesenteroides (83.7%) or Leu conostoc citreum (14%) using molecular techniques. Despite their presence i n French cheeses, the role of L. citreum in traditional technologies has no t been determined, probably because of the lack of strain identification cr iteria. Only one strain of Leuconostoc lactis and Leuconostoc fallax were i dentified in this collection, and no Weissella paramesenteroides strain was found. However, dextran negative variants of L. mesenteroides, phenotypica lly misclassified as W. paramesenteroides were present. The molecular techn iques used did not allow us to separate strains of the three L. mesenteroid es subspecies (mesenteroides, dextranicum and cremoris). In accordance with previously published results, our findings suggest that these subspecies m ay be classified as biovars. Correlation found between phenotypes dextranic um and mesenteroides of L. mesenteroides and cheese technology characterist ics suggests that certain strains may be better adapted to particular techn ological environments.