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ARS Home » Midwest Area » Urbana, Illinois » Soybean/maize Germplasm, Pathology, and Genetics Research » Research » Publications at this Location » Publication #223668
Title: New legume hosts of Phakopsora pachyrhizi based on greenhouse evaluations

Author
item SLAMINKO, 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: 3/31/2008
Publication Date: 6/1/2008
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 (fungal name Phakopsora pachyrhizi) was first described in Japan in 1903. It is a serious disease on soybean in Africa, Asia, Australia, and South America. There are over 150 host species of P. pachyrhizi reported, all of which belong to the legume family. The objective of this study was to determine if U.S.-native or –naturalized legume species identified as hosts of P. pachyrhizi in greenhouse trials could become infected with the pathogen under field conditions. A total of 80 accessions representing 52 species in 29 genera were infected in the 2006 and 2007 field trials. This is the first report showing the broad host range of P. pachyrhizi based on field infections in the U.S. This information is important to researchers interested in the biology of the pathogen and the epidemiology of this disease in terms of its spread and potential occurrence on other legume pathogens.

Technical Abstract: Phakopsora pachyrhizi, the causal organism of soybean rust, was first found on Glycine max in the continental U.S. in 2004, and subsequently on Pueraria lobata, Desmodium tortuosum, and three Phaseolus species in the field. The pathogen has been reported to occur on over 150 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 U.S.-native or –naturalized legume species identified as hosts of P. pachyrhizi in greenhouse trials could become infected with the pathogen in the field. A total of 263 entries were tested in 2 years in areas where rust occurred in experimental plots in Quincy, FL. Lesion type and sporulation were recorded, and P. pachyrhizi was confirmed by the presence of sporulating uredinia and/or polymerase chain reaction (PCR) assay. A total of 80 accessions representing 52 species in 29 genera were infected in the 2006 and 2007 field trials. Of these, 35 species in 21 genera produced sporulating uredinia. The remaining 17 species had lesions without sporulation and were confirmed to be infected with P. pachyrhizi with a PCR assay. This is the first report showing the broad host range of P. pachyrhizi based on field infections in the U.S. Some of these hosts grow in the southern U.S., and could, like kudzu, serve as over wintering hosts for P. pachyrhizi.