DNA sequence and RFLP analysis of Pleurotopsis longinqua from three disjunct populations

Abstract

The known distribution of Pleurotopsis longinqua is restricted to southeastern Australia, New Zealand, Patagonia, and the northern Pacific coast of North America. Previous studies demonstrated that isolates from all of these areas were sexually compatible (i.e., were the same biological species). Intercompatibility studies, however, did not provide information about genetic (evolutionary) relationships among the disjunct populations. Restriction fragment patterns of the nuclear ribosomal ITS1-5.8S-ITS2 were compared for isolates from each geographical region to estimate genetic divergence. Only one enzyme, Taq I, discriminated between different collections. To further examine genetic divergence, the ITS1-5.8S-ITS2 region was sequenced for one collection from each geographical area. Only four base-pair differences were observed among isolates from New Zealand, Argentina and Washington State. The remarkable similarity of these collections suggests that the current disjunct distribution is not very old.

Key Words:

• Agaricales
• Panellus longinquus
• restriction fragment length polymorphism
• ribosomal DNA
• Tricholomataceae