Function of two tandemly duplicated immune receptor genes in disease resistance and its temperature sensitivity

Within the context of climate change, temperature-resilient disease resistance mechanisms are expected to be of value to crop breeders and farmers. SNC1 is a central regulator of temperature-sensitive plant immunity in Arabidopsis thaliana. We have identified a BrSNC1 ortholog in Brassica rapa that is located next to the FocBr1 gene for resistance against Fusarium oxysporum. TILLING mutants were identified in both genes, and preliminary tests suggest that a Brsnc1 mutant allele provides temperature resilient resistance against Leptosphaeria maculans, whereas a focBr1 mutant allele was hypersusceptible to this fungal pathogen.
For this Undergraduate Vacation Bursary, the student Erin McDonagh will be testing advanced backcross generations to confirm the above-mentioned observations. A segregating population of the focBr1 line exists. Approximately 50 progeny plants will be tested at 20oC and 25oC in controlled environment cabinets for their susceptibility to L. maculans. Cotyledons will be used for KASP marker genotyping, whereas true leaves will be used to assess disease severity after spot inoculations.
Out-segregant wild-type and Brsnc1 mutants will be used to compare their susceptibility to L. maculans. Infected leaf samples will be harvested and analysed for pathogen biomass using established qPCR methodologies.
It is anticipated that successful completion of this project will contribute to a publication in an international peer-refereed journal.