|Genomics and effector characterization of the novel sugar beet pathogen Fusarium secorum|
Z. BIAN (1), R. De Jonge (2), G. Secor (1), M. Bolton (3). (1) North Dakota State University, Fargo, ND, U.S.A.; (2) Ghent University, Ghent, Belgium; (3) USDA ARS, Fargo, ND, U.S.A.
Sugar beet is an important source of sucrose for human consumption throughout the world. A new disease of sugar beet, named Fusarium yellowing decline, was recently found in in the Red River Valley of MN and ND. This disease is caused by a novel pathogen named <i>Fusarium secorum</i>. To investigate the evolutionary origin of <i>F. secorum</i>, we conducted phylogenetic analyses of the concatenated alignment of approximately 7,000 conserved single-copy core orthologs across 20 <i>Fusarium</i> species for which the entire genome is sequenced. These analyses resulted in the generation of a robust species topology that clusters <i>F. secorum</i> closely to <i>F. acutatum</i> in the <i>F. fujikuroi</i> species complex. Pathogens such as <i>F. secorum</i> secrete proteins during infection called ‘effectors’ that help establish disease. Here, candidate effectors were identified by screening the set of 15,872 predicted proteins with several bioinformatics tools combined with RNA-seq data. To characterize putative effectors, we developed a transformation system using polyethylene glycol–mediated transformation. Several mutant lines have been made with an effector deleted from the genome using a split-marker knock-out strategy. To explore their role in pathogenicity, mutant strains have been inoculated to sugarbeet and compared to WT <i>F. secorum</i>. These effector characterization results and a detailed analysis of the <i>F. secorum </i>genome will be presented.