Asking Probing Questions: Can Fluorescentin situ Hybridization Identify and Localise Aquatic Hyphomycetes on Leaf Litter?

Based on partial sequences of 16S rRNA of 8 strains of the nectrioid group, a fluorescently labeled oligonucleotide was designed for in situ hybridization. It reacted with mycelia of 4 Heliscus lugdunensis strains, but not with mycelia of Cylindrocarpon destructans, Flagellospora curta, F. curvula, or Fusarium aquaeductuum. Much weaker signals were found with conidia. Staining with Rhodamine 123 showed that mitochondria in conidia were intact. When fungal mycelia were observed on alder or maple leaves, the specificity of the probe was maintained, but there was some interference due to autofluorescence of leaf parts and algal pigments.