Bacteria were isolated from necrotic lesions on a horse chestnut tree (Aesculus hippocastanum) with bleeding canker in Hamburg, Germany. Sequencing of the rDNA-ITS region revealed great similarity to pathovars of Pseudomonas syringae. Pseudomonas syringae pv. aesculi was identified by sequence homology of the gyrase B gene. This is the first report of P. syringae pv. aesculi in Germany. Phytophthora was not detected.

SummaryIsolates of the dry rot fungus,Serpula lacrymans, and of the morphologically similar wild merulius,S. himantioides, were investigated by amplified ribosomal DNA restriction analysis (ARDRA) of the internal transcribed spacer (ITS) region to prove this method as diagnosis tool for the economically important indoor rot fungi. The technique uses the polymerase chain reaction (PCR) to amplify the relatively variable sequences of the ITS region arranged between the highly conserved portions of the 18S and 28S RNA genes of the nuclear ribosomal DNA (rDNA) repeat unit. Subsequent digestion of the amplicon with restriction endonucleases may exhibit differences at species and subspecies level. Using the universal ITS 1/ITS 4 primer combination, the ITS region of all isolates ofS. lacrymansandS. himantioideswas amplified. The size of the amplified products was about 630bp in both species, as estimated from agarose gel electrophoresis. Digestion of the amplicon with the endonuclease pairsAluI/HhaI andAvaII/MboII, respectively, revealed identical rDNA-ITS fragments for the isolates of both species, indicating their genetic relationship. On the other hand, digestion withBglI/HinfI andHaeIII/TaqI, respectively, separated the fungi by means of different fragment patterns. Thus, ARDRA-ITS proved to be suited for the identification of both fungi.

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The internal transcribed spacer (ITS) of the nuclear ribosomal DNA (rDNA) of the main fungal species causing wood rot damages in European buildings was amplified by the polymerase chain reaction (PCR). After sequencing the ITS, fungus-specific oligonucleotide primers were designed for taxon-specific priming PCR. These DNA marker molecules were suitable for the differential diagnosis of the Dry rot fungus, Serpula lacrymans, the Wild merulius, S. himantioides, the Oak polypore, Donkioporia expansa, the Brown cellar fungus, Coniophora puteana, the Broad-spored white polypore, Antrodia vaillantii, the Sap polypore, Tyromyces placenta, and the Yellow-red gill polypore, Gloeophyllum sepiarium. Each specific marker identified isolates of its respective target species. Cross reaction with 'foreign' fungi was the exception. Species detection from rot samples in buildings was possible, since DNA from contaminating organisms does not response to the marker molecules. The diagnosis was rapid, since preceding fungal pure cultures, special DNA extraction/purification and restriction by endonucleases are not required.