Phylogenetic Analysis, Vegetative Compatibility, Virulence, and Fungal Filtrates of Leaf Curl Pathogen from Celery.

Leaf curl of celery, caused by sensu lato, has been reported in the United States. A multilocus phylogenetic analysis with three genes was conducted with a collection of isolates from celery ( = 23) and noncelery ( = 29) hosts to evaluate their taxonomic position within sensu lato. The three DNA regions used for phylogenetic analysis included the introns of the glutamine synthase and glyceraldehyde-3-phosphate dehydrogenase genes, and the partial sequence of the histone3 gene. Moreover, celery and noncelery isolates were evaluated for vegetative compatibility and pathogenicity on celery. Culture filtrates from celery and noncelery 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 . The celery isolates were grouped into six vegetative compatibility groups, indicating that the population was not clonal. Isolates of from celery (22 of 23) and other hosts (26 of 29) caused leaf curl symptoms. Isolates of , , and were pathogenic but did not cause leaf curl symptoms. Isolates of , , and 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.