Molecular phylogenetic relationships amongst <e1>Alternaria</e1> species and related fungi based upon analysis of nuclear ITS and mt SSU rDNA sequences

To elucidate relationships among <e1>Alternaria</e1>, <e1>Ulocladium</e1>, and <e1>Stemphylium</e1> species, nuclear internal transcribed spacer (ITS) and mitochondrial small subunit (SSU) ribosomal DNA (rDNA) sequences from 18 <e1>Alternaria</e1>, four <e1>Ulocladium</e1> and four <e1>Stemphylium</e1> spp. were determined and compared. Phylogenetic analysis of the ITS and SSU rDNA sequences, performed by the neighbour joining and maximum parsimony methods, revealed that the <e1>Stemphylium</e1> spp. were phylogenetically distinct from the <e1>Alternaria</e1> and <e1>Ulocladium</e1> spp. Most <e1>Alternaria</e1> spp. and the <e1>Ulocladium</e1> spp. were placed together in a large <e1>Alternaria</e1>/<e1>Ulocladium</e1> clade. Within this large clade, the <e1>Alternaria</e1> spp. clustered into several distinct species-clades, most of which correlated with species-groups previously established based upon morphological characteristics. The <e1>Ulocladium</e1> spp. were placed into two species-clades, each of which also included <e1>Alternaria</e1> spp. <e1>A. longissima</e1> was distantly related to the other <e1>Alternaria</e1> spp., as well as the <e1>Ulocladium</e1> and <e1>Stemphylium</e1> spp. Based upon ITS and nuclear 18S rDNA sequence identities, <e1>A. longissima</e1> was most closely related to <e1>Leptosphaeria</e1>.