Phylogenetic relationships between Bursaphelenchus nematodes
Molecular tools (PCR-RFPL, sequence analysis of rDNA) were used in Japan to analyse the phylogenetic relationships between Bursaphelenchus nematodes. Isolates of Bursaphelenchus xylophilus (EPPO A1 quarantine pest) from: Japan (3 pathogenic isolates and 2 non-pathogenic), China (1), USA (1), Canada (4) and isolates of B. mucronatus from Japan (3), China (1) and France (1) were studied. Results showed a clear distinction between B. xylophilus and B. mucronatus. Among B. xylophilus isolates, the pathogenic Japanese isolates and the isolates from China and USA were identical. The non-pathogenic isolates from Japan were slightly distinct. The Canadian isolates of B. xylophilus showed more variability and appeared clearly as a separate cluster. The authors felt that this could reinforce the hypothesis of an introduction of B. xylophilus from USA into Japan, but further studies on a larger number of US isolates are needed. Among B. mucronatus isolates, a greater variability was observed and at least two distinct groups (from Asia, from Europe) could be distinguished.
Sources
Iwahori, H.; Tsuda, K.; Kanzaki, N.; Izui, K.; Futai, K. (1998) PCR-RFLP and sequencing of ribosomal DNA of Bursaphelenchus nematodes related to pine wilt disease.
Fundamental and applied Nematology, 21(6), 655-666.