Detection of Heterobasidion annosum s. l. [(Fr.) Bref.] in Norway spruce by polymerase chain reaction

Internal transcribed spacer (ITS) sequences of the rDNA repeat unit of Heterobasidion annosum were used to design specific primers for the detection and quantification of this important forest pathogen by polymerase chain reaction (PCR). Specificity of detection was cross-checked against a variety of other fungi (saprophytes, root pathogens, mycorrhizal fungi) which may occur in the same environment. As little as 1 pg fungal DNA (equiv. to 10-40 genomes) could be detected in 200 ng spruce root DNA (from 1 mg fresh spruce root). The Heterobasidion -specific primers allowed simultaneous detection of Armillaria spp. in multiplex PCR. The method was successfully applied to increment cores of Norway spruce from the forest region Tharandter Wald (Saxonia, Germany), Oberbarenburg (East Ore Mountains, Saxonia) and Oberschleissheim (north of Munich, Bavaria).