Host range of Cercospora apii and C. beticola and description of C. apiicola, a novel species from celery

Abstract

The genus Cercospora is one of the largest and most heterogeneous genera of hyphomycetes. Cercospora species are distributed worldwide and cause Cercospora leaf spot on most of the major plant families. Numerous species described from diverse hosts and locations are morphologically indistinguishable from C. apii and subsequently are referred to as C. apii sensu lato. The importance and ecological role that different hosts play in taxon delimitation and recognition within this complex remains unclear. It has been shown that Cercospora leaf spot on celery and sugar beet are caused respectively by C. apii and C. beticola, both of which are part of the C. apii complex. During this study we characterized a new Cercospora species, C. apiicola, which was isolated from celery in Venezuela, Korea and Greece. The phylogenetic relationship between C. apiicola and other closely related Cercospora species was studied with five different gene areas. These analyses revealed that the C. apiicola isolates cluster together in a well defined clade. Both C. apii and C. beticola sensu stricto form well defined clades and are shown to have wider host ranges and to represent distinct species.

• Ascomycetes
• Cercospora apii complex
• Cercospora leaf spot
• molecular phylogeny
• species boundaries
• taxonomy

The authors thank H.D. Shin, N. Pons and A.N. Jama for respectively supplying the infected Apium leaf materials from Korea, Venezuela and Greece. This research was financially supported by the CBS-Odo van Vloten Stichting, and the Royal Netherlands Academy of Arts and Sciences.