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Research efforts in my laboratory focus on the molecular biology of interactions between fungal pathogens of plants and their hosts, with an emphasis on the role of toxins and reactive oxygen species in pathogenicity. A major area of interest focuses on fungi in the genus Cercospora and the role of their photoactivated toxin cercosporin in disease development. Cercosporin generates reactive oxygen species that damage host cells and allow for successful pathogenesis. We are isolating and characterizing genes from the fungus that encode resistance to cercosporin, both to understand the molecular basis of toxin resistance as well as for engineering Cercospora-resistant plants using tobacco as a model system. Another project focuses on the role of light-activated toxins in the Black Sigatoka disease of banana, caused by Mycosphaerella fijensis. We are identifying polyketide gene clusters in the M. fijiensis genome and are characterizing the products and their role in disease development. Our goal is to gain an understanding of fungal pathogenicity factors and to use this information for the development of disease-resistant plants.