Identification of genes conferring resistance to bird cherry-oat aphid in Hordeum spontaneum

Bird cherry-oat aphid (BCA, Rhopalosiphum padi L.) presents a significant challenge to barley production both through feeding and virus transmission. Currently, there are no commercial barley cultivars with resistance to BCA.

Partial resistance has been identified in the wild barley (Hordeum spontaneum) accession Hsp5 and introduced into modern germplasm via backcrossing. The genomic region conferring resistance was located to an 11 Mbp region on chromosome 2H.

Preliminary analyses have identified five putative resistance genes within or adjacent to this region which are differentially expressed between the susceptible parents and the resistant parent Hsp5 and four resistant backcross lines.In this project, I will extend the search for candidate genes beyond resistance genes through a transcriptome-wide analysis of transcriptional response to aphid infestation in the selected genotypes.

Candidate genes will be either knocked out in resistant (Hsp5) or overexpressed in susceptible genotypes to confirm their effect on resistance to BCA. I will assess whether the causative gene(s) is conferring resistance to other aphid species as well.

A reference-quality genome of Hsp5 will be generated to facilitate accurate gene identification and quantification of gene expression.

Genetic markers associated with aphid resistance are highly interesting for barley breeders and will be made available to them to speed up selection for aphid resistance.