"Metabolic novelties in the Irish potato famine pathogen, Phytophthora infestans" by Melania Abrahamian, Ph.D. candidate (MCBL program).
Abstract. Phytophthora infestans, the causal agent of Late Blight of potato, is a significant biotic threat to global food security. Little is known about the metabolism of the oomycete P. infestans and how it adapts to different growth conditions and host tissues. We focused our studies on the metabolism of P. infestans, since one key to understanding host-pathogen interactions is learning about the nutrient acquisition strategies and metabolism of the pathogen. We included transcriptomics, metabolomics, proteomics and bioinformatics approaches in our research. Our studies reveal the contribution of the nitrate assimilation pathway to the pathogenesis of P. infestans. In addition, our research confirms the presence of the second half of glycolysis pathway in mitochondria, contradicting the canon that glycolysis in eukaryotes is cytosolic. Moreover, our studies demonstrate mitochondrial localization of serine biosynthesis enzymes, which form a pathway that generates serine from the glycolytic intermediate 3-phosphoglycerate. In this regard, our studies reveal that a cytosolic form of the serine pathway, which occurs in most eukaryotes, is missing from oomycetes. Therefore, we propose that the colocalization of the glycolytic and serine enzymes in mitochondria is necessary to maintain fitness in these organisms. We suggest that the novel enzymes could be targets for chemicals to control P. infestans, one of the most devastating plant pathogens.