Mapping Wheat Stem Rust Resistance Genes
The Rouse lab is interested in preventing crop losses to rust disease. Ug99 stem rust and Asian soybean rust are two fungal diseases that affect wheat and soybean, respectively, and pose imminent threats to the world’s food supply. They are caused by the rust pathogens, Puccinia graminis f. sp. tritici (Pgt) and Phakopsora pachyrhiz, respectively.
- In wheat, resistance to Ug99 stem rust in an established cultivar, Gabo 56, has been mapped to a locus containing a spate of NB/LRR resistance genes near the Yr5 marker. The Rouse lab would like to identify additional markers nearby that segregate with the resistance phenotype. Toward this goal, they have crossed Gabo 56 with the reference susceptible cultivar, Chinese Spring (CS) wheat, developing separate resistant and susceptible F3 bulk progeny, which should have a block of completely segregated DNA in the vicinity of the resistance locus. Additionally, two EMS mutants of Gabo 56 that lost their resistance phenotype were also collected. The transcriptomes of the two parents (Gabo 56 & CS), the resistant and susceptible bulk progeny, and the 2 EMS mutants were sequenced to great depth.
- Much effort by others has concentrated on the comparative analysis of the host’s infection response to fungus between susceptible and resistant plants. This project takes a different perspective, and will look for factors that make a plant more receptive or compatible/susceptible to fungal infection and the conservation of these factors across monocots (barley) and dicots (soybean). The hope is that this strategy will help identify common genes or pathway components responsible for general host susceptibility to rust pathogenesis. It should be noted that in this project barley will be used at the host in lieu of wheat, as it is a more genetically tractable genome (though also unsequenced at this time).
A story about this research appeared on the MSI website in February 2014.
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