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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #368165

Research Project: Utilizing Plant Pathogens as Biological Control Agents of Invasive Weeds in the United States

Location: Foreign Disease-Weed Science Research

Title: Uromyces rebeccae sp. nov., a newly described rust on the federally endangered plant, California sea-blite (Suaeda californica)

item BRUCKART, WILLIAM - Retired ARS Employee
item Thomas, Jami
item ABBASI, MEHRDAD - Purdue University
item AIME, CATHERINE - Purdue University
item Frederick, Reid
item Tancos, Matthew

Submitted to: Mycologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2020
Publication Date: 5/6/2020
Citation: Bruckart, W.L., Thomas, J.L., Abbasi, M., Aime, C.M., Frederick, R.D., Tancos, M.A. 2020. Uromyces rebeccae sp. nov., a newly described rust on the federally endangered plant, California sea-blite (Suaeda californica). Mycologia. 112(3):543-551.

Interpretive Summary: Suaeda californica is a federally endangered plant species that is related to Salsola tragus (Russian thistle), a non-native invasive weed that causes significant economic losses in Western pastures and rangelands. A potential fungal biological control agent is being evaluated for managing Russian thistle populations in the Western United States, but there is a need to characterize diseases of closely related native plant species which may be at risk in the presence of the introduced microbial agent. A native rust disease of Suaeda species was identified in California and discovered to be a new rust species. Knowledge about native rust diseases of Suaeda species, and in particular, S. californica, is vital to conducting a proper post-release biological control agent monitoring program.

Technical Abstract: Rust disease was observed on populations of Suaeda californica near Morro Bay, California, U.S. The pathogen was identified as a species of Uromyces based on spore morphology and sequence analysis. The isolate was compared to previously described Uromyces spp. infecting members of Chenopodiaceae, prompting a taxonomic re-evaluation of Uromyces species on Suaeda. Herein, we describe Uromyces rebeccae sp. nov., which can be differentiated from the closely related U. chenopodii (syn.: Aecidium chenopodii-fruticosi), based on host range, teliospore morphology, and nuclear ribosomal large subunit DNA sequences. The new combination, U. chenopodii-fruticosi comb. nov., is made for Aecidium chenopodii-fruticosi, the oldest name for Eurasian Suaeda rust. Finally, we determined that U. giganteus likely does not occur in the U.S. and that the rust of S. taxifolia in the U.S. likely comprises a third, yet unnamed taxon, different from both U. rebeccae, and U. chenopodii-fruticosi. This is the first record of a rust fungus on S. californica. An identification key for Uromyces species reported on Chenopodiaceae is provided.