Response of Pyronema domesticum to volatiles from microbes, seeds, and natural substrata

Abstract

Volatiles emanating from fungi, bacteria, germinating or killed seeds, and nonsterile or sterile natural substrates (decaying wood, partially decayed oak duff, and garden soil) were tested for their effects on Pyronema domesticum, a pyrophilous discomycete. Mycelial growth was strongly stimulated by volatiles from Schizophyllum commune and inhibited by volatiles from Streptomyces griseus but otherwise was generally unaffected. Volatiles from Chaetomium globosum, a second Pyronema domesticum culture, Trichophea abundans, or Trichoderma viride had little or no effect on numbers of apothecia produced. Fewer apothecia formed with volatiles from Bacillus subtilis, Cyathus stercoreus, Dipodascopsis uninucleatus, Poronia aedipus, Proteus vulgaris, Micrococcus luteus, and Streptomyces griseus. Volatiles from all bacteria and Dipodascopsis uninucleatus impaired development of the ascogenous system. Elongated asci without ascospores formed in the presence of Proteus vulgaris. Apothecia did not form in the presence of volatiles from Sordaria fimicola, Schizophyllum commune, Rhizopus nigricans, germinating seeds, nonsterile wood, or charred duff. Volatiles from autoclaved seeds, nonsterile or autoclaved soil or duff, wood ashes, and sterile wood are strongly inhibitory for apothecial development and permitted only a few apothecia to form.