In this study, three
phenetically identical Penicillium isolates, collected recently
during a project conducted to investigate the bioaerosol in
a restoration laboratory in Italy, which morphologically
resemble Penicillium raistrickii but can be distinguished
from the latter on the basis of macro- and microscopic
characteristics, were subjected to a phylogenetic investigation
to obtain a better taxonomic resolution and to gather
information on their evolutionary relationships. As molecular
markers related to the rRNA genes, we used the
internal transcribed spacers (ITS1, ITS2) including the 5.8S
In addition, cmd gene sequences (approx. 600 bp) were
obtained for P. simile sp. nov. (holotype; Supplementary
Table S1) and for the P. raistrickii strains A2a–8 and 3Ba–
AP–1 (Supplementary Table S1). The introns were bounded
by GT–AG splice sites; the two isolates of P. raistrickii
yielded identical cmd sequences. A BLAST analysis showed
that the cmd gene sequences of P. simile displayed 86%
sequence similarity with the cmd gene from strains of
P. scabrosum. In the cmd region we examined, P. simile
displayed unique cmd gene sequences that distinguished it
from P. raistrickii. In particular, the P. simile and P. raistrickii
strains (Supplementary Table S1) had different nucleotides
(sequence divergence value of approx. 6.5 %) in the intron
regions (the third and the fourth intron were slightly
different in length due to the presence of indels)