Differences in molecular characteristics between Cronartium quercuum from Japan and fusiform rust from USA

haracteristics were compared among Cronartium quercuzzm f. sp . densiflorae and C. quercuum f. sp, thurzbergii from Japan ami C. quercuum f.sp. fusifomze, fusiform rust from the USA. We examined the PCR-amplifield internal transcribed spacer (ITS) regions of ribosomal DNA from Japanese and American sources of aeciospores by restriction fragment length polymorphism (RFLP) analysis and nucleotide sequences. The ITS regions of six collections from Pinus densflora and four collections from P. thunbergii from Japan and five collections from the native American hosts P. taeda or P. e l l io t t i i were amplif ied by PCR. The RFLP pat terns with the three enzymes Dra I, Hinf I and Toq I showed clear differences between the two Japanese formae speciales an the American C. quercuum f. sp. fusiforrne. No differences were found in e RFLP patterns between f f . spp. densif lorae Nucleotide sequences of the ITS2 region confirmed the ween ff. sp. densij7orae and jksiforme. Comparisons with btained from GenBank database on the other fornuze speciales in C. quercuum also comfirmed the dist inct iveness off . sp. densiflorae. These molecular data supported ological differences reported earlier between the Asiam and Ame in the C. quercuum complex.