PRIMER SETS DEVELOPED TO AMPLIFY CONSERVED GENES FROM FILAMENTOUS ASCOMYCETES ARE USEFUL IN DIFFERENTIATING FUSARIUM SPECIES ASSOCIATED WITH CONIFERS

We examined the usefulness of primer sees designed to amplify introns within conserved genes in filamentous ascomycetes to differentiate 35 isolates representing six different species of Fusarium commonly found in association with conifer seedlings. We analyzed restriction fragme nt length polymorphisms (RFLP) in five amplified PCR products from eac h Fusarium isolate. The primers used in this study were constructed on the basis of sequence information from the H3, H4, and beta-tubulin g enes in Neurospora crassa. Primers previously developed for the interg enic transcribed spacer region of the ribosomal DNA were also used. Th e degree of interspecific polymorphism observed in the PCR products fr om the six Fusarium species allowed differentiation by a limited numbe r of amplifications and restriction endonuclease digestions. The level of intraspecific RFLP variation in the five PCR products was low in b oth Fusarium proliferatum and F. avenaceum but was high in a populatio n sample of F. oxysporum isolates. Clustering of the 35 isolates by st atistical analyses gave similar dendrograms for H3, H4, and beta-tubul in RFLP analysis, but a dendrogram produced by intergenic transcribed spacer analysis varied in the placement of some F. oxysporum isolates.