Resolving the complex of Diaporthe (Phomopsis) species occurring on Foeniculum vulgare in Portugal

Diaporthe species and their Phomopsis anamorphs are endophytes and pathogens oil a wide range of plant hosts, and are responsible for several diseases, some of which are of economic importance. Species in this genus have been described mainly on the basis of host association and to a lesser extent on their micromorphology. However, studies have revealed that host association is of minor taxonomic importance, due to the wide host ranges of some species. Moreover, more than one species can occur on a single host. On the other hand, morphological characters are not always suitable for species definition because of their plasticity and overlap between different species. Foeniculum vulgare is an herbaceous plant known to harbour a complex of Diaporthe and Phomopsis species. In this study, this complex is resolved and several taxa are delineated. An intensive sampling of Diaporthe species and Phomopsis anamorphs found on F. vulgare in Portugal was done and a collection of isolates was established in culture. Isolates were characterised and grouped according to their microsatellite-primed PCR (MSP-PCR) profiles. Representative isolates were subsequently selected for a molecular phylogeny based on the rDNA ITS region (ITS1-5.8S-ITS2). Combining morphological, cultural and molecular data, four species were distinguished from F. vulgare. Diaporthe angelicue is shown to be the most common pathogen of this host in Portugal. Diaporthe lusitanicae is newly described, whereas the teleomorph of Phomopsis theicola was revealed to be distinct from Diaporthe theicola, and is described as Diaporthe neotheicola.