Experimental systems were established for the molecular analysis of different developmental stages of Glomus mosseae. RNA and DNA were simultaneously extracted from ectocarpic spores, chlamydospores, dormant and germinating sporocarps and extraradical hyphae. A β-tubulin gene fragment was obtained by PCR from spore genomic DNA and further analysed. β-tubulin RNA expression could be monitored during the fungal life cycle with a gene-specific primer by RT–PCR using an internal cRNA standard.