Insight into mitochondria function and evolution from studies of a plant pathogenic stramenopile

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In eukaryotes, metabolic reactions are typically partitioned between different cellular compartments. One set of metabolic reactions thought to occur only in the cytoplasm is glycolysis, the chemical reactions that generate cellular energy. In this project, the PI will investigate a deviation from this well-accepted textbook definition of glycolysis in Oomycetes, a group of plant and animal pathogens, in which part of glycolysis is proposed to occur in mitochondria. The project will provide a better understanding of the origins and diversity of these metabolic reactions in the potato pathogen Phytophthora infestans. The novel oomycete metabolic pathways that will be studied also represent potential targets for inhibitors that can be exploited to develop new disease control strategies. This will yield economic and environmental benefits, raise the sustainability of agricultural production, and increase food security. The project also supports scientific education and the training of a diverse workforce through the participation of graduate and undergraduate students at a Hispanic-Serving Institution.Our current understanding of glycolysis is based largely on a few model organisms. This project focuses on the role of mitochondria and metabolic compartmentalization in that organelle in glycolysis, using as a model the potato pathogen Phytophthora infestans. This filamentous eukaryotic microbe is a member of the oomycete group of the stramenopile kingdom. Since the evolutionary history of stramenopiles is distinct from that of classic model organisms, this project will shed light on the origins of mitochondria and diversity. The first objective of the project is to study glycolytic enzymes that are found in oomycete mitochondria. The classic view is that glycolysis takes place in the cytosol, but enzymes representing the payoff phase of glycolysis are predicted to also occur in oomycete mitochondria. These novel enzymes will be studied by localizing the relevant enzymes using fluorescent tags, silencing their genes, and assessing their activity. The second objective of the project is to examine P. infestans mitochondria more broadly with a goal of identifying other novel pathways in the organelle. The research will integrate evolutionary biology, cell biology, biochemistry, and molecular genetics.