Heterologous Expression Of An ABC Transporter From Sclerotinia homoeocarpa To Determine Its Role In Fungicide Detoxification.

Sclerotinia homoeocarpa causes dollar spot disease on turfgrass, and fungicide resistance to S. homoeocarpa is a common problem on golf courses in the United States. In a previous study, we found that overexpression of ABC-G transporter, ShMR4, was associated with reduced sensitivity to multiple fungicides in field isolates of S. homoeocarpa. In brief, the field isolates exhibited significantly reduced sensitivity to a sterol demethylation inhibitor (DMI) fungicide, propiconazole, as well as decreased sensitivities to a succinate dehydrogenase inhibitor fungicide (SDHI), boscalid, and a dicarboximide fungicide, iprodione. These isolates also showed overexpression of ShMR4 in the absence and presence of three chemicals. In order to validate the role of ShMR4 in detoxification of these compounds, we are investigating the substrate specificity of this efflux transporter using a heterologous yeast expression system. The system has been utilized to verify the involvement of ABC transporters to sensitivity of multiple fungicides and plant- and microbe-derived compounds in other plant pathogenic fungi.

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