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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #322135
Title: A polymerase chain reaction assay for ascosporic inoculum of Sclerotinia species

Author
item JONES, SUZIE - Tasmanian Institute Of Agricultural Research
item PILKINGTON, STACEY - Tasmanian Institute Of Agricultural Research
item Gent, David - Dave
item HAY, FRANK - Tasmanian Institute Of Agricultural Research
item PETHYBRIDGE, SARAH - Cornell University

Submitted to: New Zealand Journal of Crop and Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2015
Publication Date: 5/26/2015
Citation: Jones, S.J., Pilkington, S., Gent, D.H., Hay, F.S., Pethybridge, S.J. 2015. A polymerase chain reaction assay for ascosporic inoculum of Sclerotinia species. New Zealand Journal of Crop and Horticultural Science. 43(3):233-240.

Interpretive Summary: The disease white mold is a widespread problem in many crops. Management of the disease is dependent on timely use of fungicides, however, fungicide applications are sometimes not needed for disease control if spores of the fungus are not present. IN this work, we developed a molecular assay to detect airborne spores of the fungus under field conditions. The assay was useful for detecting the pathogen in bean fields, and may provide a tool to better target fungicides during periods of inoculum presence and avoid unneeded treatments.

Technical Abstract: A PCR assay was developed which amplified a 170-bp fragment of the intergenic spacer region of Sclerotinia sclerotiorum, the cause of white mould. Sensitivity was 10 S. sclerotiorum ascospores per DNA extraction (0.2 ascospores per PCR reaction). The presence of soil did not affect sensitivity at 50, 100 and 500 ascospores/DNA extraction, but reduced sensitivity at 25 and 10 ascospores/DNA extraction by 10% and 30%, respectively. The assay did not amplify DNA of Botrytis cinerea but detected S. minor and S. trifoliorum. Utility of the test for detection of S. sclerotiorum ascospores in bean fields was demonstrated using rotating impaction samplers over three seasons. The use of the test in combination with an impaction sampler may provide benefits in time, sensitivity and specificity compared to visual identification and enumeration of spores from traps only. This system may provide an opportunity to schedule fungicides during periods of inoculum for disease management.