Diversity of the internal transcribed spacer of rDNA in morels

Abstract

The internal transcribed spacer (ITS) of rDNA was analysed by PCR/RFLP in 66 strains belonging to 11 putative species of the Morchellaceae and 3 species of the Discinaceae. For certain taxa, in particular Morchella esculenta, Morchella conica, and Morchella elata, isolates from distant geographical origins were available. Nevertheless, no intraspecific variations of ITS length and restriction was noted. All genera were separated and within Morchella; four putative species could be clearly distinguished in the group of the yellow morels (sectio adnatae). In contrast, no distinction could be obtained between the compared taxa in the group of the black morels (sectio distantes). Sequence analyses of the ITS were performed in one strain of seven putative Morchella. The sequence comparison confirmed the distinctions within the yellow morels and allowed us to separate one putative taxon from the others in black morels. Only the 5,8 gene could be aligned in all sequenced samples. The ITS1 and ITS2 sectors could only be aligned within the black and yellow morels, respectively. The genetic and phylogenetic distances between black and yellow morels, respectively revealed by maximum parsimony and neighbour joining analyses, both confirm the great distance between these species groups and address the question of a separation in the genus Morchella.Key words: Morchellaceae, Discinaceae, ITS.