Characterization and Phylogenetic Analysis of Four Root-Knot Nematode Species Using DNA Amplification Fingerprinting and Automated Polyacrylamide Gel Electrophoresis. Thomas J. Baum. Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29634-0377. Peter M. Gresshoff(2), Stephen A. Lewis(1), and Ralph A. Dean(1). (1)Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29634-0377, and (2) Plant Molecular Genetics, Center for Legume Research, University of Tennessee, Knoxville 37901 -1071 U.S.A. MPMI 7:39-47. Accepted 8 October 1993. Copyright This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of Ihe source. The American Phytopathological Society, 1994.

Species identification and quantification of genolypic diversity in root-knot nematodes were achieved by DNA amplification fingerprinting (DAF). Purified DNA from isolates of Meloidogyne arenaria, M. incognita, M. java-nica, and M. hapla was amplified by low-stringency amplification reactions with 20 single-octamer primers of arbitrary sequence. Amplification products were separated by electrophoresis in precast polyacrylamide minigels and visualized by silver staining with an automated electrophoresis and staining unit (PhastSystem). Fingerprinting data were analyzed with PAUP 3.1.1 using the Wagner parsimony method. Fourteen primers successfully amplified nematode DNA. Five primers revealed very conspicuous polymorphisms between species, while the remaining primers showed moderate to small differences. Polymorphisms between populations of the four species from the southeastern United States could also be detected. Phylogenetic analyses for the four species showed closer relat-edness between M. arenaria and M.javanica than between M. arenaria and M. incognita. M. hapla was most distant from M. arenaria, M. javanica, and M. incognita. These results are in agreement with phylogenetic trees derived from different characters. DAF utilizing automated polyacrylamide gel electrophoresis and silver staining is highly reproducible and offers excellent resolution, optimal sensitivity, unequaled speed, and the simplicity of automation.