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Poster Presentations


Poster Presentations


Adhesion of Phakopsora pachyrhizi urediniospores to soybean leaves

Presenter: M. C. Velez-Climent

All authors and affiliations: M. C. VELEZ-CLIMENT (1), D. G. Luster (2), S. A. Isard (1), and E. D. DeWolf (1). (1) Plant Pathology, Penn State University, University Park, PA; and (2) USDA-ARS, FDWSRU, Fort Detrick, MD

Soybean leaves (cv. Williams) were inoculated with Phakopsora pachyrhizi urediniospores and incubated at optimal conditions of ~100% RH and 20C. A timeline of spore adhesion was created by removing samples from the incubator at specific time points after inoculation. The leaves were washed by simulating raindrops to remove unattached spores, and the remaining spores were dyed with lactophenol cotton blue and counted under a light microscope. Urediniospores started adhering to soybean leaves within the first hour of inoculation and nearly all adhered spores had a germ tube structure. This suggests that spore adhesion is dependent on metabolic activity and germination. Isolates from Alabama and Louisiana were used to perform two separate repetitions of the experiment and appeared to have very different germination rates. Even so, their adhesion timeline was almost parallel and both showed a germ tube structure on the majority of the adhered spores.

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