Archaeophytopathology of Phakopsora pachyrhizi, the soybean rust pathogen

James S. Haudenshield, Glen L. Hartman

Research output: Contribution to journalArticlepeer-review


Herbarium specimens are useful to compare attributes of the past to attributes of today and predictions into the future. In this study, herbarium specimens from 1887 to 2006 were used to identify Phakopsora pachyrhizi and P. meibomiae, the two known fungal species that cause soybean rust. Historically, these two species differed in geographic distribution, with P. pachyrhizi confined to Asia and Australia, and P. meibomiae confined to the Americas. In our analyses, herbariumspecimens were used to determine whether it was possible to extract adequate useful DNA from the fungal structures. If present, quantitative PCR primers specific to P. pachyrhizi, P. meibomiae, or to a third group inclusive of many rust species could be used to speciate the fungus. Of the 38 archival specimens, 11 were positive for P. pachyrhizi, including a 1912 specimen from Japan; 15 were positive for P. meibomiae, including a 1928 specimen from Brazil and two 1923 specimens from the Philippines; and 12 (including all African accessions) were negative for both species. Five specimens were positive in the more inclusive rust assay; all had been labeled as P. pachyrhizi and none were on soybean. These results demonstrate the feasibility of DNA genotyping in archaeophytopathological investigations.

Original languageEnglish (US)
Pages (from-to)575-579
Number of pages5
JournalPlant disease
Issue number5
StatePublished - May 1 2015

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science


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