Taxonomic Characterization and Experimental Host Ranges of Four Newly Recorded Species ofAlternariafromJapan

Abstract

AbstractAlternariafungi are important plant pathogens. Here, we identified three species new to theJapanese mycoflora:Alternaria celosiae,Alternaria crassaandAlternaria petroselini. We proposed a new name forA. celosiae(E.G.Simmons &Holcomb)Lawrence,Park &Pryor, a later homonym ofA. celosiae(Tassi)O.Săvul. To characterize these and a fourth morphological taxon,Alternaria alstroemeriae, which was recently added toJapan'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 rDNA. The pathogenicity of ourA. alstroemeriaeisolate was strictly limited toAlstroemeriasp. (Alstroemeriaceae), but the species was phylogenetically indistinguishable from other small‐sporedAlternaria.Alternaria celosiaeonCelosia argenteavar.plumosa(Amaranthaceae) was also pathogenic toAmaranthus tricolor, toAlternanthera paronychioidesand weakly toGomphrena globosa(all Amaranthaceae) and formed a clade with the formerNimbya celosiae.Alternaria crassaonDatura stramonium(Solanaceae) was also pathogenic toBrugmansia × candidaandCapsicum annuuminSolanaceae, 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 thatA. crassa,Alternaria capsiciandAlternaria daturicolawere conspecific.Alternaria petroselinionPetroselinum crispum(Apiaceae) was pathogenic to five species in the tribeApieae as well as representatives ofBupleureae,Coriandreae,Seliaeae andScandiceae inApiaceae. Both phylogeny and morphology suggested conspecificity betweenA. petroseliniandAlternaria selini.