PHYLOGENETIC ANALYSIS OF SOME LEUCONOSTOCS AND RELATED ORGANISMS AS DETERMINED FROM LARGE-SUBUNIT RIBOSOMAL-RNA GENE-SEQUENCES - ASSESSMENT OF CONGRUENCE OF SMALL-SUBUNIT AND LARGE-SUBUNIT RIBOSOMAL-RNA DERIVED TREES

The large-subunit ribosomal RNA gene sequences of Leuconostoc carnosum, Leuc. mesenteroides, Leuc. oenos, Leuc. paramesenteroides and Lactobacillus confusus were determined by direct sequencing of enzymatically-amplified DNA. Comparative analysis of the large-subunit rDNA sequences revealed that the leuconostocs form three distinct lines of descent: Leuconostoc sensu stricto, Leuc. paramesenteroides group of organisms, and Leuc. oenos. The distance matrix tree constructed from the large-subunit sequence data was in excellent agreement with that derived from small-subunit sequences, and demonstrates the 'synchrony' of the two chronometers. The results of the present and earlier sequence analyses indicate the taxonomy of the genus Leuconostoc is in need of revision, and that the Leuc. paramesenteroides group of organisms and the species Leuc. oenos represent distinct phylogenetic units, separate from Leuconostoc sensu stricto.