Phylogenetic analysis of nucleotide sequences from the ITS region of terverticillate Penicillium species

The genetic variability within 600 bp of DNA sequence from the ribosomal in ternal transcribed spacers (ITS 1 and ITS 2) and the 5.8 S rRNA gene was ex amined in 52 strains belonging to 29 terverticillate taxa in Penicillium su bg. Penicillitim from diverse sources and locations. The sequenced region i s extremely conserved within the terverticillate penicillia, with only 29 p ositions differing in one or more taxa. The highest degree of ITS variabili ty was seen among the species close to Penicillium roqueforti (P. roquefort i, P. carneum and P paneum) whereas the ITS variability was very low betwee n closely related taxa, e.g. among the taxa near P. aurantiogriseum. The re lationships among the terverticillate penicillia, and related teleomorphs i n Eupenicillium, were analysed from bootstrapped ITS sequence data sets usi ng the neighbour-joining method. The terverticillate penicillia form a well supported clade with Eupenicillium crustaceum. Sequence analysis generally confirmed the overall taxonomy in Penicillium subg. Penicillium but relati onships between all the terverticillate taxa could not be clearly establish ed due to the low degree of ITS variability. Nevertheless, clades of Penici llium species sharing environmental characteristics did emerge, e.g. specie s growing on protein and lipid rich substrates (e.g. P. crustosum and P. co mmune), species prevalent in dry habitats (e.g. P. chrysogenum and P. nalgi ovense), and those prevalent on carbohydrate rich substrates (e.g. P. auran tiogriseum and P. freii).