Eleven cultures representing eight genera of five
families of Loculoascomycetes were obtained from ATCC and IMI.
Partial 18S and
28S nuclear ribosomal DNA (rDNA) were amplified using
PCR and sequenced. About 1100 bps of 18S rDNA (NS1/NS4 region)
and 459 bps of 28S rDNA (F63/R635 region) for each taxon
were subject to phylogenetic analysis using parsimony. The
reconstructed phylogenetic trees supported the separation of
two monophyletic groups, containing the type genera of the
Leptosphaeriaceae and the Pleosporaceae, respectively. The
members of the Leptosphaeriaceae (sensu Barr)
consisted of the paraphyletic clade in the phylogenetic trees.
The members of the Pleosporaceae (sensu Barr)
plus Pyrenophora trichostoma formed a
monophyletic clade. The results generally supported the
separation of the Leptosphaeriaceae from Pleosporaceae and the
placement of P. trichostoma, and Comoclathris
baccata in the Pleosporaceae. The taxonomic position of
Pleospora betae, whose coelomycetous
anamorph is more closely related to Leptosphaeriaceae, was
not well resolved because of low bootstrap values and decay indices.
Leptosphaeria bicolor, whose ascospore morphology is
not congeneric with the type of the genus, L.
doliolum, does not belong to
Leptosphaeria based on the 18S sequence data. The
taxonomic disposition of Lewia, Pyrenophora,
and Comoclathris based on the
phylogenetic analyses are discussed.