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Poster: Molecular & Cellular Plant-Microbe Interactions: Biochemistry & Cell Biology


A sensitive method for quantifying cercosporin, a fungal-derived secondary metabolite, in plant tissue
J. SMITH (1), J. Lay (2), B. Bluhm (2) (1) University of Arkansas, U.S.A.; (2) University of Arkansas, U.S.A.

Cercospora species infect a wide range of host plants, including soybean and maize. Many species of Cercospora produce the phytotoxic secondary metabolite cercosporin. The role of cercosporin as a virulence factor has been demonstrated in several Cercospora species. However, it is not clear whether cercosporin is important for virulence in all species of Cercospora. To gain a more complete understanding of the role of cercosporin in plant pathogenesis, sensitive methods for its detection and quantification are required. Therefore, the objective of this research was to develop a mass spectrometry based method for quantification of cercosporin from plant tissues with high sensitivity. To this end, extraction, sample cleanup, chromatographic separation, and mass spectrometry based detection methods were developed and optimized. The use of liquid chromatography coupled with a triple quadrupole mass spectrometer allowed detection of cercosporin at concentrations as low as 1 ng/ml. Currently, the feasibility of using this method for quantifying cercosporin in soybean leaves and seed infected with C. kikuchii and maize leaves infected with C. zeae-maydis is being examined. A sensitive method for detecting and quantifying cercosporin will provide a valuable tool for determining the role of this compound in virulence among Cercospora species.