Electrophoretic Isoenzyme Variation in Kluyveromyces Populations and Revision of Kluyveromyces marxianus (Hansen) van der Walt

Abstract

Natural isolates of Kluyveromyces from a variety of habitats were compared on the basis of seven isoenzyme patterns. Some strains of Candida considered to be Kluyveromyces anamorphs, as well as one strain each of Candida sake, Saccharomyces cerevisiae, and Pichia JEuxuum, were also examined. The isoenzyme patterns readily substantiated the relationships between the anamorphs and their putative teleomorphs and the nonmember status of strains not belonging to the genus. A multivariate analysis of the electrophoretic patterns indicated that isolates belonging to the Kluy veromyces lactis and Kluy veromyces marxianus deoxyribonucleic acid reassociation groups are not phenotypically continuous with one another or with the former species Kluyveromyces dobzhanskii, and thus we propose to reinstate these taxa as separate species. Taxa previously described as Kluyveromyces thermotokrans and Kluyveromyces waltii also appeared to constitute reproductively isolated natural populations. When the results of isoenzyme electrophoresis were compared with deoxyribonucleic acid reassociation data and with mating compatibility patterns determined by other workers, we found that deoxyribonucleic acid relatedness gives a more accurate view of relationships among Kluyveromyces species.In 1984, the genus Kluyveromyces van der Walt emend. van der Walt underwent a major revision (15). Based on strain hybridization studies ( 5 ) , Kluyveromyces bulgaricus,

An analysis of inter- and intraspecific genetic variabilities in the Kluyveromyces marxianus group of yeast species for the reconsideration of the K. lactis taxon

“…drosophilarum strains within the K. lactis taxon. This emended K. lactis species could be subdivided artificially into two varieties, in accordance with the ecological arguments proposed by Sidenberg and Lachance (1986), var. lactis for lactose-positive heterothallic strains isolated from dairy products and var.…”

“…drosophilarum, (Lachance, 1998), constituted by the assembling of several strains sharing a common physiological type. This subspecies delineation was suggested by Sidenberg and Lachance (1986), who proposed the division of K. lactis into these two artificial but easily recognizable varieties. They based the separation of these varieties primarily on ecological grounds; thus, K. lactis var.…”

“…The subdivision of K. lactis into varieties lactis and drosophilarum was proposed by Sidenberg and Lachance (1986) and is maintained in the last monographs on the genus Kluyveromyces (Lachance, 1993(Lachance, , 1998. This division was based on physiological capabilities (lactose utilization) and ecological criteria (isolation source).…”

“…Additional studies involving electrophoretic isoenzyme pattern analysis (Sidenberg and Lachance, 1986), deoxyribonucleic acid base sequence relatedness (Fuson et al, 1987;Vaughan-Martini and Martini, 1987), chromosomal karyotyping (Sor and Fukuhara, 1989;Belloch et al, 1998b), RAPD-PCR analysis (Molnar et al, 1996) and mtDNA restriction analysis (Ragnini and Fukuhara, 1988;Belloch et al, 1997) were puzzling because they were indicative of the existence of genetic heterogeneity within K. lactis, supporting the differentiation between the varieties lactis and drosophilarum but, at the same time, a marked variation is also observed within varieties as well.…”

Deoxyribonucleic Acid Base Sequence Relatedness among Members of the Yeast Genus Kluyveromyces

“…The level of DNA base sequence relatedness between K. waftii and K. thermotoferans, the only members of the high-G+C group, has not been investigated. Isoenzyme analysis, however, suggests that they are distinct (33).…”