IDENTIFICATION OF THE GENUS ARMILLARIA (F R-FR) STAUDE AND HETEROBASIDION-ANNOSUM (FR.) BREF. IN NORWAY SPRUCE (PICEA-ABIES [L.] KARST.) AND DETERMINATION OF CLONAL DISTRIBUTION OF A-OSTOYAE-GENOTYPES BY MOLECULAR METHODS

Methods based on the polymerase chain reaction (PCR) for generating mo lecular markers are illustrated by two important forest pathogens, Arm illaria spp. and H. annosum. Using the primer pairs ARM-1/ARM-2 and HE T-7/HET-8, derived from sequences of the ''internal transcribed spacer '' (ITS) regions of the rDNA repeat, Armillaria spp.- and H. annosum-s pecific DNA fragments were amplified by PCR. This PCR-based detection method allows a rapid and definite diagnosis of both important root an d butt rot pathogens in different substrates or plant tissues, especia lly in early stages. Genetic variability among 20 A. ostoyae-isolates from different geographical origins was studied. UPGMA cluster analysi s of random amplified polymorphic DNAs (RAPDs) profiles generated by 1 0 decamer random primers (OPA 01-10) grouped the isolates in subcluste rs at similarity levels between 40% and 96%, indicating high intraspec ific genetic variation. The potential role of historical and current s pread of spruce plants on the genetic variation of A. ostoyae in Europ e is discussed. The established polymorphic DNA markers were used to d etermine the population structure, dynamics and spatial distribution o f A. ostoyae-''genets'' in areas colonized by the fungus. First invest igations revealed different distribution strategies of A. ostoyae, whi ch may be mediated by climatic factors, location (e.g., soil character s), and pollutants.