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Updated: Jun 4, 2026
06:09
An Easy and Flexible Inoculation Method for Accurately Assessing Powdery Mildew-Infection Phenotypes of Arabidopsis and Other Plants
Published on: March 9, 2021
Molecular detection tools for the powdery mildew genus Podosphaera
Samantha Rose Thompson1, Michael Bradshaw2, Rachel P Naegele3,4
1Michigan State University, Plant, Soil, and Microbial Sciences , 758 Wilson Rd., East Lansing, Michigan, United States, 48824; thom1759@msu.edu.
Plant Disease
|June 3, 2026
Summary
New qPCR assays accurately detect powdery mildew species, including strawberry and apple pathogens. These tools improve early detection and management of fungal diseases in crops.
Area of Science:
- Plant Pathology
- Mycology
- Molecular Diagnostics
Background:
- Powdery mildews are significant threats to crops, caused by obligate biotrophic fungi in the Erysiphaceae family.
- Conventional identification methods struggle to differentiate closely related species, hindering precise diagnostics.
- Accurate species identification is crucial for effective disease management and understanding host-pathogen interactions.
Purpose of the Study:
- To develop species-specific TaqMan qPCR assays for detecting key powdery mildew pathogens.
- To target the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) nuclear gene for enhanced diagnostic resolution.
- To provide a molecular toolset for early detection, monitoring, and accurate species identification of Erysiphaceae.
Main Methods:
- Developed and validated species-specific TaqMan qPCR assays targeting the GAPDH gene.
- Collected and sequenced powdery mildew specimens from various hosts across multiple US states (2020-2024).
- Evaluated assay specificity and sensitivity using environmental samples and infection time-course studies.
Main Results:
- Developed highly specific and sensitive qPCR assays for *Podosphaera shepherdiae* and *P. leucotricha*.
- Achieved low detection limits (10 pg DNA for *P. shepherdiae*, 5 pg for *P. leucotricha*) with no cross-reactivity.
- Demonstrated consistent detection of *P. shepherdiae* in strawberry (*Fragaria x ananassa*) from early to late infection stages (5 dpi onwards).
- Documented four novel global host-pathogen associations.
Conclusions:
- The developed qPCR assays offer a robust molecular tool for early and accurate detection of powdery mildew fungi.
- These assays facilitate improved disease management strategies through precise species identification.
- The study advances species-specific diagnostics within the Erysiphaceae family, supporting further research and application.
