Taxonomy of Bursaphelenchus xylophilus
The taxonomic relationships of Bursaphelenchus xylophilus (EPPO A1 organism) and B. mucronatus were studied in Canada. The studies were based on interspecific and intraspecific cross-hybridization and DNA analysis. Five geographic isolates of B. xylophilus from North America and Japan and two isolates of B. mucronatus from France and Japan were cross-hybridized.
Intraspecific hybridization between the B. xylophilus isolates produced fertile offspring while intraspecific hybridization between the B. mucronatus isolates from France (female) and Japan (male) produced fertile Fn generations, but the reciprocal cross died out. Interspecific hybridization between the B. xylophilus isolates and B. mucronatus produced a F1 that died out in most of the crosses in which the female was B. mucronatus and the male B. xylophilus.
The authors assumed that their studies support the distinct species status of B. mucronatus and B. xylophilus and suggest that B. xylophilus and B. mucronatus from France and Japan come from a common ancestor. The also concluded that the B. mucronatus isolates from France and Japan have a separate species status.
Sources
Riga, E.; Beckenbach, K.; Webster, J.M. (1992) Taxonomic relationships of Bursaphelenchus xylophilus and B. mucronatus based on interspecific and intraspecific cross-hybridization and DNA analysis.
Fundamental and Applied Nematology 15, 391-395.