Bulgariella pulla, a Leotiomycete of uncertain placement, with an uncommon type of ascus opening

ABSTRACT

Bulgariella pulla (Leotiomycetes) is redescribed with the addition of characters of the ascus, spores, and habitat that were previously unconsidered. The ascus dehiscence mechanism in Bulgariella is unusual among Leotiomycetes. In this genus, asci lack a pore and open by splitting to form valves. Phylogenetic analyses of partial sequences of translation elongation factor 1-α (TEF1-α), the second largest subunit of RNA polymerase II (RPB2), and the 18S and 28S nuc rRNA genes determined that Bulgariella belongs within Leotiomycetes but without conclusive assignment to an order or family. A comparison of the nuc rDNA internal transcribed spacers 1 and 2 plus the 5.8S gene (ITS) determined that Bulgariella isolates from the USA, Norway, and Sweden had 100% sequence similarity, and an isolate from Chile had 99.3% similarity with these isolates. These results support the proposition that these collections represent a single species, B. pulla. Bulgariella sphaerospora, a more recently described species, is confirmed as conspecific with B. pulla.

KEYWORDS:

• Ascus dehiscence
• Helotiales
• Pezizomycotina
• phylogeny
• taxonomy

ACKNOWLEDGMENTS

We thank Michaela Schmull and Genevieve Tocci (FH) for the loan of type, authentic material, and other specimens studied. We thank Thomas Læssøe and Sven-Åke Hanson for sending collections of B. pulla from Norway and Sweden used in our morphological and molecular studies; Thomas Læssøe provided a photograph and field data for the fresh collection from Sognefjorden, western Norway, collected by Alfred Granmko, used in FIG. 2A, and another one photographed by Sven-Åke Hanson. Danny Haelewaters is thanked for assistance with DIC. We thank Bill Neill for initially bringing this fungus to our attention. We express sincere appreciation to Rosanne Healy for her careful review of the manuscript, valuable suggestions, and help with Adobe Illustrator. We thank Keith Seifert for thorough reviewing and suggesting improvements to the manuscript.

Additional information

Funding

At Harvard University, the work was funded by the Farlow Herbarium and the David Rockefeller Center for Latin American Studies through the “Emilio Botín Santander Visiting Scholarship.” T.I. is grateful for this support.