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ARS Home » Midwest Area » Urbana, Illinois » Soybean/maize Germplasm, Pathology, and Genetics Research » Research » Publications at this Location » Publication #218837

Title: New Legume Hosts of Phakopsora pachyrhizi Based on Greenhouse Evaluations

Author
item SLAMINDO, T - UNIV OF ILLINOIS
item Miles, Monte
item Frederick, Reid
item Bonde, Morris
item Hartman, Glen

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/8/2008
Publication Date: 5/1/2008
Citation: Slaminko, T.L., Miles, M.R., Frederick, R.D., Bonde, M.R., Hartman, G.L. 2008. New legume hosts of Phakopsora pachyrhizi based on greenhouse evaluations. Plant Disease. 92:(5)767-771.

Interpretive Summary: Soybean rust was first found in the continental U.S. in 2004, and has been found on soybean, kudzu, Florida beggarweed, and three Phaseolus species in the field so far in the U.S. The pathogen has been reported to occur on over 90 legume species worldwide, and it is likely to infect native and introduced legume species in the U.S. The objective of this study was to determine if 176 species representing 57 genera of legumes, the majority of which are either native or naturalized to soybean growing areas of the U.S., could be hosts of P. pachyrhizi. The fungus causing soybean rust was confirmed by the presence of sporulating uredinia and/or immunological assay on 65 new species in 25 genera; 12 of these genera have not been reported previously as hosts. Many of the newly identified hosts grow in the southern U.S., and could, like kudzu, serve as over wintering hosts for P. pachyrhizi. This information is important to pathologist, epidemiologist, and others interested in knowing more about potential over wintering hosts in the U.S.

Technical Abstract: Phakopsora pachyrhizi, the causal organism of soybean rust, was first found in the continental U.S. in 2004, and has been found on soybean, kudzu, Florida beggarweed, and three Phaseolus species in the field. The pathogen has been reported to occur on over 90 legume species worldwide, and it is likely to infect native and introduced legume species in the U.S. The objective of this study was to determine if 176 species representing 57 genera of legumes, the majority of which are either native or naturalized to soybean growing areas of the U.S., could be hosts of P. pachyrhizi. Between one and three accessions of each species, a total of 264 accessions, were inoculated with a mixture of four isolates of P. pachyrhizi. Severity and sporulation were rated on a 1 to 5 scale at 14 and 28 days after inoculation. P. pachyrhizi was confirmed by the presence of sporulating uredinia and/or immunological assay on 65 new species in 25 genera; 12 of these genera have not been reported previously as hosts. Many of the newly identified hosts grow in the southern U.S., and could, like kudzu, serve as over wintering hosts for P. pachyrhizi.