Real-Time PCR Detection of Clarireedia spp., the Causal Agents of Dollar Spot in Turfgrasses

• Published in: Plant disease Vol. 104; no. 12; p. 3118
• Main Authors: Groben, Glen, Clarke, Bruce B, Murphy, James, Koch, Paul, Crouch, Jo Anne, Lee, Sangkook, Zhang, Ning
• Format: Journal Article
• Language: English
• Published: United States 01-12-2020
• Subjects: Agrostis - genetics; Ascomycota - genetics; Plant Diseases; Plant Leaves; Real-Time Polymerase Chain Reaction; qPCR; bentgrass; pathogen detection; Rutstroemiaceae
• ISSN: 0191-2917
• DOI: 10.1094/PDIS-04-20-0726-RE

Dollar spot is one of the most economically important diseases of turfgrasses. Recent taxonomic revisions have placed the dollar spot fungal pathogens in the new genus
, with five species described. The main goal of this study was to develop a quantitative real-time PCR (qPCR) molecular detection assay based on the internal transcribed spacer (ITS) of the ribosomal RNA genes to quantify the abundance of
spp. from environmental (field) samples. The qPCR assay was able to detect isolates of the four tested
spp. but did not cross react with nontarget fungi, including closely related taxa, other turfgrass pathogens, or other fungal species commonly isolated from turfgrass. The assay is capable of detecting as little as 38.0 fg (3.8 × 10
g) of
genomic DNA in 3 h. The qPCR assay detected
spp. in both symptomatic and asymptomatic creeping bentgrass (
) foliar tissue.
spp. were rarely detected in the thatch or soil, indicating that these pathogens are not widely distributed in these areas of the environment. The fact that the pathogen was detected in asymptomatic tissue suggests that creeping bentgrass may be able to tolerate a certain quantity of the pathogens in leaves before disease symptoms appear; however, further research is needed to validate this hypothesis.