LAUSR

Leaf curl of celery, caused by Colletotrichum acutatum sensu lato, has been reported in the U.S. A multi-locus phylogenetic analysis with three genes was conducted with a collection of isolates from celery (23) and non-celery (29) hosts to evaluate their taxonomic position within C. acutatum sensu lato. The three DNA regions used for phylogenetic analysis included the introns of glutamine synthase (GS) and glyceraldehyde-3-phosphate dehydrogenase (GPDH), and the partial sequence of the histone3 (his3) gene. Moreover, celery and non-celery isolates were evaluated for vegetative compatibility and pathogenicity on celery. Culture filtrates from celery and non-celery isolates were also evaluated for their ability to reproduce leaf curl symptoms. A total of 23 celery isolates were evaluated based on phylogenetic analysis, which showed that all celery isolates were closely related and belonged to the newly described species C. fioriniae. The celery isolates were grouped into six vegetative compatibility groups indicating the population was not clonal. Twenty two of 23 isolates of C. fioriniae from celery and other hosts (26 of 29) caused leaf curl symptoms. Isolates of C. acutatum, C. nymphaeae, and C. godetiae were pathogenic but did not cause leaf curl symptoms. Isolates of C. lupini, C. johnstonii, and C. gloeosporioides were not pathogenic on celery. In addition, cell-free fungal culture filtrates caused leaf curl symptoms on celery indicating that certain isolates produce a metabolite that can cause leaf curl symptoms on celery, possibly indole acetic acid (IAA).