Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 5/8/1997
Publication Date: N/A
Technical Abstract: Sigler promoted the varieties of Emmonsia parva (vars. crescens and parva) to species rank on the basis of morphological and physiological differences and on the lack of mating reactions among some of the strains. In order to provide another means of identifying the species and to examine the genetic variation among strains of a species, DNA sequences were determined for the ITS and part of the LSU rDNA from 12 strains of E. parva and 18 strains of E. crescens. There are numerous nucleotide differences in the homologous rDNA and ITS regions of the species E. parva and E. crescens strongly supporting the separation of taxa made by Sigler. The sequence difference are consistent with those found between distinct species in other fungal genera (yeasts, filamentous fungi). Among isolates of each species, the strains separate into two subgroups. Within each subgroup, sequences are nearly identical, between subgroups, the numbers of sequence differences is similar to differences between sibling fungal species. E. parva and E. crescens both contain morphologically cryptic subtypes that may deserve elevation to a recognized taxonomic level of either species or variety.