Abstract Detail

Mycological Section

Powers, Rob [1], James, Timothy [1].

Sexual Selection and The Buller Phenomenon in the Bipolar Basidiomycete, Coprinellus disseminatus.

Sexual selection, a form of natural selection involving choice of mates, has been observed in a wide range of sexual organisms and among diverse clades of eukaryotes. To date, little research has been conducted on sexual selection and its mechanisms in the mushroom-forming members of the Basidiomycota. Our research seeks to address the questions: Is sexual selection occurring in fungi and how does it impact their mating system? Which traits are subject to sexual selection? In many Basidiomycetes, the typical life-cycle involves mating via the reciprocal transfer of nuclei among two monokaryotic mycelia of compatible mating type, leading to the formation of a dikaryon (n+n). Since plasmogamy occurs long before karyogamy, each nucleus in a dikaryon can behave autonomously, providing opportunities for conflict or cooperation between nuclei. The Buller Phenomenon is one example of such autonomous behavior, in which a nucleus in a dikaryon can migrate and fertilize a mating-type compatible monokaryon, leading to opportunities for choosiness by the monokaryotic “female” mycelium. Conversely, nuclear migration may be solely or partially determined by competition between the nuclei for access to the monokaryotic mycelium, a form of “male competition”. To better understand sexual selection in mushroom-forming fungi we conducted a series of Buller pairings using a set of mating-compatible strains of the bipolar mushroom species Coprinellus disseminatus, crossed in all possible dikaryon/monokaryon pairings. Our results show that that sexual selection occurs in C. disseminatus, that the fertilizing nucleus is not strongly correlated with mating type, and that there is a strong preference for outcrossing among non-sibling nuclei. Additionally, we show that monosporous isolates consistently outcompete dikaryotic strains when simultaneously crossed to a compatible monokaryon, suggesting that “male competition” among dikaryotic nuclei in the Buller phenomenon has an associated fitness cost.

1 - University of Michigan, Ecology and Evoltionary Biology, Kraus Natural Science Bldg., Rm. 1008, 830 North University, Ann Arbor, MI, 48109, USA

Keywords:
Sexual selection
Buller phenomenon
Coprinellus.

Presentation Type: Oral Paper:Papers for Sections
Session: 56
Location: Salon 1/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 9:00 AM
Number: 56005
Abstract ID:952
Candidate for Awards:MSA Best Oral Presentation Award by a Graduate Student