Pseudomonas syringae pv. aesculi associated with horse chestnut bleeding canker in Germany

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.     

Data bank of rDNA-ITS sequences from building-rot fungi for their identification

Wood Science and Technology -     

Fast molecular detection of Pseudomonas syringae pv. aesculi in diseased horse chestnut trees

A molecular technique was used to detect the bacterium Pseudomonas syringae pv. aesculi in horse chestnut trees (Aesculus hippocastanum), affected by the recently recognized European ‘Pseudomonas horse chestnut bark disease’. The technique helped identify the pathogen within 6 h of sample preparation including DNA extraction, polymerase chain reaction (PCR) and electrophoresis until gel documentation. PCR primer pairs derived from the gyrase B gene sequence were used. Because of the great similarity in the gyrase B gene sequences of the numerous closely related P. syringae pathovars, the primers were not only totally specific to the pathovar aesculi, but also detected a few other pathovars. The assumption that other bacteria should not occur at least near to a necrotic lesion of a horse chestnut tree was corroborated by sequence identity of the PCR products obtained with the gyrase B gene sequence of P. syringae pv. aesculi. Koch’s postulates were fulfilled for an isolate of P. syringae pv. aesculi obtained from a diseased horse chestnut tree sampled in Hamburg in 2007.     

Data bank of rDNA-ITS sequences from building-rot fungi for their identification

To identify building-rot fungi in culture and from rot host tissue, the rDNA-ITS region of 18 species was determined by PCR and sequencing: Serpula lacrymans, S. himantioides, Meruliporia incrassata, Leucogyrophana mollusca, L. pinastri, Coniophora puteana, C. arida, C. marmorata, C. olivacea, Antrodia vaillantii, A. serialis, A. sinuosa, A. xantha, Oligoporus placenta, Donkioporia expansa, Gloeophyllum abietinum, G. sepiarium, and G. trabeum. Sequences were deposited in the international databases. Unknown samples can be identified via homology. Received 4 December 2001 The work belongs to our project `Investigations on internal wood decay fungi for their characterization and identification', kindly funded by the German Research Foundation (DFG).