GENETIC DIFFERENTIATION WITHIN THE EUROPEAN RACE OF GREMMENIELLA-ABIETINA

Twelve random amplified polymorphic DNA markers were variable within t he European race of Gremmeniella abietina var. abietina (GAA-EU) in Eu rope. Three distinct DNA amplification profiles (amplitypes) appeared to be correlated with ecotypic origin. The northern amplitype was pres ent exclusively in northern Europe in plantations and natural stands o f Pinus sylvestris and in plantations of P. contorta and apparently wa s adapted to the presence of deep, long-lasting snow cover in the wint er. An alpine amplitype was found exclusively in the Alps at altitudes above 2000 m on P. cembra, P. mugo, P. sylvestris and Larix lyalli an d also appears to represent an ecotype adapted to conditions of deep s now cover. The third amplitype, the European amplitype, was present th roughout Europe and ranged from the Scandinavian countries and extende d south to the Apennine mountains of northern Italy. Most of the GAA-E U samples tested from North America had RAPD profiles identical to tho se of the European amplitype indicating that the origin of this introd uced pathogen could be central Europe. However, some of the samples fr om North America had RAPD profiles that did not match any found in Eur ope. The internal transcribed spacers of the ribosomal DNA repeat subu nit were amplified and digested with restriction enzymes Hae III and M sp I. These restriction sites were polymorphic between the North Ameri can (GAA-NA). race and the EU race of G. abietina but were homogeneous among the three amplitypes described above. The rDNA restriction and RAPD profiles also indicated that GAA-NA was absent from the samples f rom Europe and that symptoms resembling those caused by GAA-NA were at tributable to the northern and alpine amplitypes.