Ashling Granahan

Graduated 2020

Investigating the role of serine proteases in basidiomycete fruiting body development and nutrient acquisition from humic-rich environments.

Agaricus bisporus, (common button mushroom), has both economic and biotechnological
significance. It is the most cultivated mushroom worldwide and the mushroom industry in Ireland
represents the largest horticultural sector. The basidiomycete fungi have a clear ecological role,
where the depolymerisation of biopolymers is a key process in the cycling of carbon, with litter
decomposition in temperate forests mainly driven by fungal activity. They constitute a major fraction
of the living biomass responsible for efficient degradation of many recalcitrant organic compounds in
soil litter and the humic layer.

The ink cap mushroom Coprinopsis cinerea (formally Coprinus cinereus), has long been regarded as
one of the best model systems for the study of basidiomycete fungi, in particular the economically
significant A. bisporus. Most attention in C. cinerea has been focused on processes such as mating
type determination and also on meiosis. Little detail is known about the other aspects of the biology of
this fungus such as the cellular mechanisms involved in the development of fruiting structures.

Serine proteinases have been shown to be significant in both post-harvest spoilage of mushrooms and
nutrient acquisition from compost. This research seeks to fully elucidate the function of serine
proteases in mushroom fruiting body development and nutrient acquisition through promoter
profiling. The aims of my research are:

1. Isolation and profiling of candidate fruiting promoters
2. Expression of SPR1 in C. cinerea and silencing of the A. bisporus SPR1 at different fruiting
body development stages
3. Investigation of endogenous serine proteases in C. cinerea
4. Determination of factors affecting the regulation of serine proteases