Ribosomal DNA intergenic spacer of indoor wood-decay fungi

Indoor wood-decay fungi are economically very important. Approximately half of the total damage caused by indoor fungi in Germany is caused by species of the Coniophoraceae. The sequence of the intergenic spacer (IGS) region of the ribosomal DNA was elucidated with the following fungi of this family: Serpula lacrymans (true dry rot fungus), S. himantioides (wild merulius), Meruliporia incrassata (North American dry rot fungus), Leuco-gyrophana pinastri (mine dry rot fungus), Coniophora puteana (brown cellar fungus), and C. marmorata (marmoreus cellar fungus). The IGS length ranges between 2584 and 3785 bp and consists of the short IGS 1 (253–440 bp), the 5S rDNA (118 bp) and the long IGS 2 (2193–3310 bp). IGS 1 is phylogenetically less informative for the investigated Coniophoraceae species. 5S rDNA is transcribed in the reverse direction. IGS 2 contains extended repeat blocks of copies of different length. Intraspecific length polymorphism as a result of different copy number occurs in M. incrassata and L. pinastri. In combination with previous results, the full-length sequence of the rDNA repeat unit is available for important indoor wood-decay fungi. The various rDNA regions can now be used for future identification of unknown sequences by BLAST and also for phylogenetic studies.