TAXONOMY OF SOME XYLARIA SPECIES AND XYLARIACEOUS ENDOPHYTES BY ISOZYME ELECTROPHORESIS

Isozyme profiles of cultures from one stromatal culture, six multispore and 46 single-spore isolates of Xylaria polymorpha, X. hypoxylon, X. carpophila, X. longipes, X. longiana, X. feejeensis, as well as of 32 Xylaria cultures isolated as endophytes were analysed by starch gel electrophoresis. Fourteen enzymes, using five buffer systems, were investigated. Principal-component analysis carried out on the electrophoretic data (electromorphs) showed a distinct grouping of the strains that corresponds to the current species concepts. Two main clusters can be distinguished. The first contains strains of X. polymorpha, X. longipes and X. feejeensis, in groups that correspond to their taxonomic arrangement. Strains of X. polymorpha from widely separated geographical provenances tend to segregate into distinct sub-clusters. In the second, strains of X. carpophila and X. hypoxylon form each one compact group, regardless, however, of their geographical origin. Of 32 endophytic Xylaria isolates investigated, 27 are included in the first duster, and 17 of them form a distinct group. Two endophytic strains might be identified as X. polymorpha by isozyme electrophoresis. Only five of the 32 endophytes are phenotypically related to X. carpophila or X. hypoxylon. A broad screening for production of pharmaceutically and agriculturally useful metabolites was also carried out on the same strains. Comparison of two separate classification analyses performed on the results of enzyme electrophoresis and screening showed no correlation between the results of the two methods. Between 70 and 80% of single-spore and endophytic isolates produced potentially useful metabolites.