Development and application of a TaqMan real-time PCR assay for rapid detection of Magnaporthe poae

Abstract

In North America, one of the most important root diseases of Poa and Festuca turf is summer patch, caused by Magnaporthe poae. Detection and identification of M. poae in infected roots by conventional culture-based methods is difficult and time consuming, typically taking 3 wk or longer to accomplish. In this study, a culture-independent, TaqMan real-time PCR assay was developed for the detection of M. poae from the roots of fungicidetreated and non-treated Kentucky bluegrass (Poa pratensis) turf. The assay was validated with the target pathogen, closely related fungal species and a number of other microorganisms that inhabit the same host and soil environment. This assay was more sensitive (could detect as little as 3.88 pg genomic DNA of M. poae), rapid and accurate compared to direct microscopic observation and isolation on a selective medium. The real-time PCR detection results corresponded closely to visual assessments of disease severity in the field. Utilization of this assay in diagnostic laboratories will enable turfgrass managers to more quickly and effectively detect and potentially reduce fungicide usage through early and accurate identification of the pathogen.

Key words:

• diagnostic assay
• fungicide
• molecular detection
• plant pathogen
• Poaceae
• qPCR
• turf
• turfgrass

Acknowledgments

The authors thank Pradip Majumdar for his help in sample collection and disease severity analysis. The China Scholarship Council supported S. Zhao for this work. The study also was supported by the New Jersey Agricultural Experiment Station, the Rutgers Center for Turfgrass Science, the US Golf Association and the New Jersey Turfgrass Foundation.