OUR NOVEL MULTISTEP APPROACH
Virulent races of Puccinia graminis f. sp. tritici (Pgt), or wheat stem rust, have caused devastating effects on cereal grains worldwide, impacting global food security. We are engineering Escherichia coli DH5α and Saccharomyces cerevisiae EBY100 to detect Pgt and improve response times to virulent strains. To detect Pgt, we are creating a device that will germinate spores from the Puccinia genus. The germinated spores produce ribitol, a sugar unique to Pgt. Our engineered DH5α will produce a fluorescent signal in the presence of ribitol, thus detecting Pgt. To detect specific virulent races of Pgt, we will modify yeast to contain the stem rust resistance gene Sr35 from Triticum monococcum; Sr35 recognizes its corresponding effector AvrSr35, secreted by Pgt, as part of the plant’s innate immune system. Using bimolecular fluorescence complementation, our yeast will detect AvrSr35, a first step in being able to indicate the virulence of the germinated Pgt spores.
Transform Escherichia coli DH5α with a plasmid carrying a promoter induced by ribitol, a compound unique to infectious structures formed by fungal spores, upstream of a fluorescent protein.
Express wheat resistance genes in transformed Saccharomyces cerevisiae EBY100 to detect virulence factors released by Pgt to distinguish whether or not the race of Pgt present is virulent to the strain of wheat.