A meiotic drive element in the maize pathogenFusarium verticillioidesis located within a 102-kb region of chromosome V

ABSTRACTFusarium verticillioidesis an agriculturally important fungus because of its association with maize and its propensity to contaminate grain with toxic compounds. Some isolates of the fungus harbor a meiotic drive element known as Sporekiller(SkK) that causes nearly all surviving meiotic progeny from anSkK× Spore killer-susceptible (SkS) cross to inherit theSkKallele.SkKhas been mapped to chromosome V but the genetic element responsible for meiotic drive and spore killing has yet to be identified. In this study, we used cleaved amplified polymorphic sequence markers to genotype individual progeny from anSkK×SkSmapping population. We also sequenced the genomes of three progeny from the mapping population to determine their single nucleotide polymorphisms. These techniques allowed us to refine the location ofSkKto a contiguous 102-kb region of chromosome V, herein referred to as theSklocus. Relative toSkSgenotypes,SkKgenotypes have one extra gene within this locus for a total of 42 genes. The additional gene inSkKgenotypes, named SKL1 forSpore Killer Locus 1, is the most highly expressed gene from theSklocus during early stages of sexual development. TheSklocus also has three hypervariable regions, the longest of which includesSKL1. The possibility thatSKL1, or another gene from theSklocus, is an essential component of meiotic drive and spore killing is discussed.