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Utilizing genomic tools to identify and characterize effectors in the novel sugar beet pathogen Fusarium secorum

Subidhya Shrestha: North Dakota State University

<div>Sugar beet is an important source of sucrose for human consumption throughout the world. Fusarium yellowing decline, caused by the novel fungal pathogen <em>Fusarium secorum</em>, is a new disease of sugar beet which was recently found in the Red River Valley of Minnesota and North Dakota. This disease is characterized by yellowing of leaves, vascular discoloration in the petiole, damping off of seedlings and the rapid death of plant at early stage. <em>F. secorum</em> produces effectors that are secreted during infection of the host. To gain a better understanding of the molecular basis of pathogenicity of this new disease, we utilized genome sequencing, transcriptome analysis, and xylem sap mass spectrometry of <em>F. secorum </em>infected-sugar beet plants to report 15,900 predicted genes, among which 527 exhibited effector characteristics. Among these candidate effector genes, 30 were highly expressed during <em>F. secorum</em> infection <em>in planta</em>. We developed a transformation system for this fungus and performed targeted gene replacement to characterize 11 candidate effector genes of which FSECE8 was identified as a virulence factor. Further studies will be directed to characterize the role of FSECE8 in pathogenicity. This study provides a valuable genomic resource for <em>F. secorum</em> and other closely related <em>Fusarium </em>spp. and sheds light on the virulence strategies of this novel pathogen.</div>