2nd Place: D3067: Enhancing sugar beet breeding efforts by identifying mechanisms and genes conferring curly top resistance

Curly top disease is caused by the beet curly top virus (BCTV) which is exclusively vectored by Circulifer tenellus, the beet leafhopper. Current management strategies for BCTV include the use of BCTV-resistant or tolerant varieties, but the underlying genetic mechanism is not known. It is critical to determine the mechanism of resistance and identify resistant gene(s) that can be implemented in breeding programs. The objectives of my project were: 1) classify the nature of curly top disease resistance in resistant (EL10) and susceptible (FC-709-2) sugar beet varieties using insect preference and performance assays and 2) characterize the volatiles emitted by the plant when fed upon by infected BLH. There was no significant difference in adult survival and reproduction on resistant and susceptible varieties suggesting that plant resistance mechanism was not antibiosis. In preference assays, BCTV-infected leafhoppers showed preference to susceptible variety compared to resistant variety at all timepoints; however, non-infected leafhoppers did not show a feeding preference. Volatile analysis is underway using GC-MS to analyze the plant response to BCTV infected leafhoppers feeding for both sugar beet varieties. Outcomes will give further understanding of the plant defense response and possible insight to changes in metabolite pathways in response to BLH feeding. These studies will be coupled with an RNASeq experiment to fully characterize the mechanism of resistance to BCTV in sugar beet. Overall, outcomes of this study help to identify mechanisms and genes associated with viral resistance in sugar beets.