Taxonomic Characterization and Experimental Host Ranges of Four Newly Recorded Species of A lternaria from J apan

Abstract A lternaria fungi are important plant pathogens. Here, we identified three species new to the J apanese mycoflora: A lternaria celosiae , A lternaria crassa and A lternaria petroselini . We proposed a new name for A . celosiae ( E . G . S immons & H olcomb) L awrence, P ark & P ryor, a later homonym of A . celosiae ( T assi) O . S ăvul. To characterize these and a fourth morphological taxon, A lternaria alstroemeriae , which was recently added to J apan's mycoflora, an integrated species concept was tested. We determined the host range of each isolate using inoculation tests and analysed its phylogenetic position using sequences of the internal transcribed spacer r DNA . The pathogenicity of our A . alstroemeriae isolate was strictly limited to A lstroemeria sp. ( A lstroemeriaceae), but the species was phylogenetically indistinguishable from other small‐spored A lternaria . A lternaria celosiae on C elosia argentea var. plumosa ( A maranthaceae) was also pathogenic to A maranthus tricolor , to A lternanthera paronychioides and weakly to G omphrena globosa (all Amaranthaceae) and formed a clade with the former N imbya celosiae . A lternaria crassa on D atura stramonium ( S olanaceae) was also pathogenic to B rugmansia  ×  candida and C apsicum annuum in S olanaceae, but not to other confamilial plants; phylogenetically it belonged to a clade of large‐spored species with filamentous beaks. Morphological similarity, phylogenetic relationship and experimental host range suggested that A .  crassa , A lternaria capsici and A lternaria daturicola were conspecific. A lternaria petroselini on P etroselinum crispum ( A piaceae) was pathogenic to five species in the tribe A pieae as well as representatives of B upleureae, C oriandreae, S eliaeae and S candiceae in A piaceae. Both phylogeny and morphology suggested conspecificity between A .  petroselini and A lternaria selini .