Phytophthora rot, caused by Phytophthora sojae, is one of the most damaging diseases of soybean (Glycine max) worldwide. This disease can be difficult to diagnose and other Phytophthora species can infect soybean. Accurate diagnosis is important for management of Phytophthora rot. The objective of this study was to evaluate polymerase chain reaction (PCR) methods for rapid and specific detection of P. sojae and diagnosis of Phytophthora rot. PCR assays using two sets of primers (PS and PSOJ) that target the ITS region were evaluated for specificity and sensitivity to P. sojae. Genomic DNA extracted from 11 species of Phytophthora and 19 other species of fungal and oomycete pathogens were used to test the specificity of each primer set. The previously published PS primers amplified DNA from P. sojae and from four other Phytophthora species using conventional PCR, indicating they are not specific for P. sojae. The new PSOJ primers amplified DNA only from P. sojae using conventional and real-time PCR and not from Phytophthora sansomeana, which has been found in soybean production areas, indicating that they are specific for P. sojae. The PSOJ primers were also used to detect P. sojae in diseased soybean tissue and infested soil. The PCR assays based on the PSOJ primers are specific, rapid, and sensitive tools for the detection of P. sojae.
Bibliographical noteFunding Information:
We thank P. Hart and R. Hammerschmidt of Michigan State University for preliminary research to identify the PSOJ primers and for granting us permission to develop and validate the assay. Support for this research is gratefully acknowledged from the University of Minnesota Agricultural Experiment Station, the Minnesota Soybean Research and Promotion Council, and the North Central Soybean Research Program. We also thank C. Floyd and J. O’Rourke for their expert technical assistance with analyzing P. sojae sequences, as well as N. Grunwald, D. Samac, A. Holm, A. Robertson, and R. Blanchette and his research group for providing isolates and DNA.
Copyright 2011 Elsevier B.V., All rights reserved.
- Molecular diagnostics
- Phytophthora rot
- Root disease