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Abstract

Barley yellow dwarf virus (BYDV) is an aphid-vectored cereal pathogen. BYDV costs the UK economy ~£60million every year in lost production. The two main BYDV vectors are the bird cherry oat aphid (Rhopalosiphum padi) and English grain aphid (Sitobion avenae). Controlling aphid population is challenging due to a diminishing portfolio of plant protection products resulting from insecticide resistance and legislation that limits use. Plant-virus-vector interactions drive the spread of plant viruses. It is poorly understood how natural genetic variation of each ‘partner’ in this three-way interaction influences virus spread. Within an aphid species the asexual progeny from a single female foundress are typically defined as clones. Aphids also harbour symbiotic bacteria (endosymbionts), which can influence their fitness, pathogen resistance and virus vectoring efficiency amongst others. Other studies have shown that different aphid clones exhibit varying efficiency in vectoring plant viruses. Here we explore if aphid genetic diversity and the bacterial endosymbionts they carry can influence the dynamics of plant-virus-vector interactions.

Description

The initial foIn this study, R. padi and S. avenae aphid clones have been collected from different regions in the UK. Their genetic diversity has been characterised using microsatellite genotyping and the presence of bacterial endosymbionts in these aphids identified using PCR. Virus transmission experiments using BYDV-PAV (R. padi) and BYDV-MAV (S. avenae) strains on these field-collected aphid clones will be conducted in the laboratory. The aim here is to

determine if there is a link between aphid genotype, endosymbiont profile, and ability to vector BYDV. Aphid survival and reproduction will also be recorded on healthy versus BYDV-infected plants. In parallel, the molecular determinants of aphid transmission specificity in BYDV will also be explored. Ultimately, the results will enable better prediction of BYDV outbreaks in the field through improved monitoring and identification of aphid clones with varying vectoring capacities.