HETEROBASIDION-ANNOSUM 5.8S RIBOSOMAL DNA AND INTERNAL TRANSCRIBED SPACER SEQUENCE - RAPID IDENTIFICATION OF EUROPEAN INTERSTERILITY GROUPSBY RIBOSOMAL DNA RESTRICTION POLYMORPHISM

Using conserved fungal ribosomal gene sequences the internal transcrib ed spacer (ITS) regions one and two (ITSI, ITS2) and the 5.8s ribosoma l RNA gene (rRNA) of Heterobasidion annosum were amplified by the poly merase chain reaction (PCR). The nucleotide sequence was determined in three European intersterility groups (ISG-S, -F and -P). Three sequen ce variants of the ITS were found in ISG-S isolates. The sequence of t he ITS of ISG-F differed by two residues from the major ISG-S sequence variant. The ISG-P sequence differed from ISG-S and ISG-F at 15-16 an d 16 residues, respectively. Amplified intergenic spacer elements were informative for ISG fingerprinting following digestion with various 4 -cutter restriction endonucleases. All differences in the restriction fragments between the ISGs were because of sequence differences in the ITS regions. The fingerprint patterns of isolates from the same inter sterility group but from different European localities were identical. These results show that ribosomal DNA finger-printing is a rapid tech nique to identify ISGs in Heterobasidion annosum.