ARS | Publication request: The rust genus Frommeëlla revisited: a later synonym of Phragmidium after all

Submitted to: Mycologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 20, 2011
Publication Date: November 17, 2011
Citation: Yun, H.Y., Minnis, A.M., Kim, Y.H., Castlebury, L.A., Aime, M.C. 2011. The rust genus Frommeëlla revisited: a later synonym of Phragmidium after all. Mycologia. 103(6):1451-1463.

Interpretive Summary: Rust fungi are a very large and diverse group of parasites that attack different kinds of plants including crop and weedy species. Related species of rust fungi tend to occur on only one group of plant hosts. In this paper the rust fungi on plants in the rose family were examined including those on blackberry as well as on a weedy plant called mock strawberry. Previously the rust fungus on the weed was considered to be quite different from the ones that occur on blackberry. This research demonstrated that the rust fungi on the weed and blackberry are closely related and should be placed in the same genus. This research will be used by plant pathologists and conservationists who need to identify the rust fungi on these plants.

Technical Abstract: Frommeëlla (Phragmidiaceae, Pucciniales, Basidiomycota) causes rust on members of tribe Potentilleae (Rosaceae). This genus currently includes two species and is typified by F. tormentillae. It has been distinguished from Phragmidium on the basis of having only one germ pore per cell of the teliospore rather than two or three and by aecial characters. Phylogenetic analyses of both currently accepted species of Frommeëlla using nLSU rDNA data suggest that Frommeëlla was derived from within a clade representing Phragmidium. Thus, Frommeëlla should be considered a later generic synonym of Phragmidium. Analyses also indicate that Frommeëlla tormentillae on Potentilla includes two cryptic taxa recognized herein as Phragmidium potentillae-canadensis and P. tormentillae. Frommeëlla mexicana on species of Potentilla formerly classified in Duchesnea is distinct from but sister to the other two species. Based on data regarding type specimens, the new combination Phragmidium mexicanum is proposed as the correct name for this species.