Interactions between bacteria and coprophilous Ascomycotina and a Coprinus species on agar and in copromes

Abstract

The effects of Flavobacterium, Methanobacterium, Pseudomonas and Staphylococcus on ascospore germination and mycelial extension in Ascobolus crenulatus, Chaetomium bostrychodes and Sordaria macrospora were studied on agar. Bacteria or their culture filtrates inhibited germination except for Methanobacterium — S. macrospora where only filtrate did so. Bacteria and filtrates reduced germ-tube extension in S. macrospora but had a less consistent effect on A. crenulatus and C. bostrychodes. Mycelial growth of C. bostrychodes and S. macrospora was inhibited by the presence of all bacteria, the effect being especially severe for the latter. By contrast, mycelial growth of A. crenulatus was stimulated by all bacteria.

When paired with Ascomycotina in copromes, bacteria generally reduced ascocarp production but had little effect on coprome dry weight losses. In the presence of all three Ascomycotina in copromes, bacteria had a differential effect on fruiting such that ascocarp production by A. crenulatus was enhanced whilst that of the other two species was reduced. The exception was Staphylococcus which inhibited fruiting in A. crenulatus and S. macrospora but had little effect on C. bostrychodes.

When all three Ascomycotina were present in copromes the addition of Coprinus to the community resulted in only S. macrospora producing ascocarps. Addition of bacteria to the community had a differential effect on the Coprinus-induced fruiting pattern, with Flavobacterium and Methanobacterium facilitating fruiting by all three Ascomycotina.