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32 EUFORGEN: Quercus suberN ORKResearch on the provenances of Quercus suberin ItalyRosanna Bellarosa and Bartolomeo SchironeDip. di Scienze dell'Ambiente Forestale e delle sue Risorse, Universita della Tuscia,01100 Viterbo, ItalyGenetic characterizationResearch aimed at the genetic characterization of several Italian Quercus suberprovenances and at the distribution of the species was carried out during 1995.Nuclear ribosomal rDNA genes were extensively used in both phylogenetic andtaxonomic studies at inter- and intraspecific levels, for identification of hybrids andfor investigation of natural populations of species (see Appels and Dvorak 1982;Bellarosa et al. 1990, 1996; Bobola et al. 1992).Previous studies carried out on the ribosomal rDNA genes of Q.suberprovenances (Bellarosa 1996) showed that the intergernc spacer (IeS) can provideuseful information with regard to the intra specific genetic variation. Therefore, itseemed opportune to extend the ongoing research to include the ITS (InternalTranscribed Spacer) as well (see Fig. 1).As already reported (Baldwin et al. 1995), the ITS region can be useful inproviding a valuable set of characters for phylogenetic reconstruction in plants, inresolving conflicts between data sets and in supporting evidence about evolution.With the recent appearance of the polymerase chain reac.tion (peR) technology, theentire ITS region and the two ITS-1/ITS-2 spacers can be easily amplified andsequenced by means of specific primers.'The ITS-l and ITS-2 amplifications and sequencing of Q. macrolepis, Q. pubescens,Q. cerds and four Italian Q. suber provenances were carried out in the laboratory ofthe Dip. di Scienze dell'Ambiente Forestale e delle sue Risor?e, and in collaborationwith F. Maggirn and R. Morocco.The most interesting data obtained from these preliminary studies concern corkoak. Among the angiosperms sequenced to date, cork oak is the first species thatshows two types of ITS-I: a short one of 181-183 bp and a long one of 212 bp. It isalso interesting that the ITS-l (181-183 bp) is the shortest intragernc spacer reportedso far for angiosperm taxa. Moreover, the four cork oak provenances seem todifferentiate among themselves at the short ITS-l nucleotide level; while the longITS-l shows an identical nucleotide sequence in all provenances. The two types of'ITS-l show sequence homology of 64.85%. The other examined Quercus speciesshow only one type of ITS-1 (212-214 bp) that is more related to the long ITS-lobserved in cork oak than to the short one.The variations observed in the nucleotide sequences of ITS-l appear to be usefulto discriminate among the species and to draft a preliminary dendrogram ofrelationships between taxa. What emerges from these results is the different18S S.SS 25S 25S/~ _______ rf~~C==========~--~~~'----~C==--IHlTS-l rrS-2 105Fig. 1.region.Organization of a ribosomal DNA gene. ITS-1/S.8SIITS-2 belong to the rr