GENETIC DIVERSITY AMONG NATURAL-POPULATIONS OF ENDOPHYTIC LOPHODERMIUM-PINASTRI FROM PINUS-RESINOSA

Isolates of the endophytic Leptostroma anamorph of Lophodermium pinast ri were collected from needles of Pinus resinosa (red pine) at three l ocations in Eastern Canada. The DNA of 69 isolates which were morpholo gically identical was subjected to RFLP analysis using two probes for repeated genomic sequences. One probe, pRWi249, was obtained from a li brary made from DNA of one of the L. pinastri isolates. The other was an rDNA probe, pTA71, derived from Triticum aestivum. The complementar y hybridization patterns of EcoR I-digested DNA obtained using these t wo probes demonstrated considerable genetic diversity in and between t he natural populations of L. pinastri. In total, 27 distinct genotypes were identified of which only three were represented at all three col lection sites. No more than 5 isolates of the same genotype were found at any one location and different genotypes were often found among is olates of the same tree. It is concluded that the probes pRWi249 and p TA71 are practical tools for screening isolates of L. pinastri and are likely to be useful for the identification and classification of thes e endophytes.