Colorimetric in situ hybridization (CISH) with digoxigenin-labeled oligonucleotide probes in autofluorescent...

We used digoxigenin-labeled probes for in situ hybridization of hyphomycetes to replace the commonly used fluorescent proof of probe binding by a colorimetric reaction. The resulting blue-purple, intracellular precipitate could be easily detected by light microscopy, and thus presented a promising method to overcome autofluorescence of fungal material and substratum. Optimal cell fixation and permeabilization procedures, as well as hybridization conditions were developed on the example of two different hyphomycetes: Phialophora sp. and Cartapip, a colorless mutant of Ophiostoma piliferum (Agra Sol).