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United States Department of Agriculture

Agricultural Research Service

Title: Detection and Quantification of Soybean Rust (Phakopsora Pachyrhizi) Spores by Quantitative Real-Time Pcr

item Miles, Monte
item Hartman, Glen

Submitted to: National Soybean Rust Symposium
Publication Type: Proceedings
Publication Acceptance Date: September 30, 2006
Publication Date: November 14, 2006
Citation: Steinlage, T.A., Miles, M.R., Hartman, G.L. 2006. Detection and quantification of soybean rust (Phakopsora pachyrhizi) spores by quantitative real-time PCR. Proceedings of the National Soybean Rust Symposium, November 14-16, 2005, Nashville, Tennessee. Available at

Technical Abstract: An important aspect of an early detection and monitoring system for soybean rust is the reliability of detection and quantification of spores from rain or spore traps. Visual evaluation of rods or slides from spore traps is time consuming and may not be accurate since other look-a-like spores from other species may provide false positives. The most reliable method for identification of soybean rust has been a PCR assay. The main objective of this study was to improve the sensitivity of the QPCR assay for detecting spores from various spore traps. A number of treatments were evaluated including different co-precipitants using fresh and heat-killed spores. The equivalent of DNA from 10 spores was detected at a range of 25 to 27 PCR cycles for fresh spores and a range of 34 to 43 cycles for heat-killed spores, depending upon the test. We have shown that the QPCR method has the sensitivity to detect few spores, but additional research needs to be completed to make this technology more consistent and widely adapted.

Last Modified: 4/22/2015
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