Abstract Detail

Mycology

Haelewaters, Danny [1], Stallman, Jeffery [1], Liu, Jingyu [1], Aime, M. Catherine [1].

Polydiscidium martynii—an enigmatic fungus placed onto the Ascomycota Tree of Life.

Polydiscidium martynii, the only species in the genus, grows on dead wood and is composed of thick, black, gelatinous somatic tissue that branches out from the base towards the apices of the ascomata. Apothecia are located on the branches, mostly towards the tips, and are composed of 8-spored asci and paraphyses embedded in a gelatinous matrix that turns blue in Melzer's reagent. The species is known from only seven collections from Guyana (1929), Trinidad (1913), and D.R. Congo (1928). No sequences exist and the evolutionary relationships of the genus Polydiscidium are uncertain, with different authors placing it in Helotiaceae, Leotiaceae, or Leotiomycetes incertae sedis. Recent collections of this species resulting from long-term fieldwork in Guyana and Cameroon led us to revisit the morphology and phylogenetic position of this enigmatic genus. Newly generated sequences of P. martynii were added to an Ascomycota-wide six-locus dataset. The resulting phylogeny showed Polydiscidium to be a member of Sclerococcales (Eurotiomycetes). Next, a four-locus (SSU, ITS, LSU, mtSSU) phylogenetic reconstruction was performed, which revealed that Polydiscidium should be considered a synonym of Sclerococcum. Finally, also micromorphological features correspond to this genus.

1 - Purdue University, Department of Botany and Plant Pathology, 915 W. State Street, West Lafayette, IN, 47907, USA
2 - Purdue University, Department of Botany and Plant Pathology, 915 W. State Street, West Lafayette, IN, 47907, USA

Keywords:
Multilocus phylogeny
Ascomycota
Eurotiomycetes
Sclerococcales
Systematics
Mycology.

Presentation Type: Poster
Session: MYP1, Mycology Posters I
Location: /
Date: Monday, July 19th, 2021
Time: 5:00 PM(EDT)
Number: MYP1002
Abstract ID:141
Candidate for Awards:MSA Best Poster Presentation Award by a Graduate Student