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Leon van Eck, Ph.D.
Aphids are phloem-feeding insects that substantially reduce crop yields around the world. Current pest-management approaches threaten to undermine ecological balance, rely heavily on expensive chemical inputs, and select for resistant insect biotypes. This study investigated differential fitness of the bird-cherry oat aphid (Rhopalosiphum padi) on three accessions of Hordeum vulgare ssp. spontaneum, the wild progenitor of cultivated barley. Data from the electrical penetration graph (EPG) technique suggest that aphids presented with WBDC 053 as a host spent significantly less time ingesting phloem sap than those infesting WBDC 117, WBDC 336, or the commercial barley line ‘Morex’ (Mx) – indicating the presence of a phloem-based resistance in WBDC 053. The plant genes SOD, LOX, and HSP70 were selected as representatives of key metabolic pathways involved in plant defense responses, namely those in the production of jasmonate. Altered regulation of these genes during aphid feeding in the various barley accessions was assessed via quantitative RT-PCR. Differential gene expression between accessions is correlated with EPG and reproductive data. This characterization of pest resistance in three wild barley accessions demonstrates the utility of crop wild relatives as sources of novel genetic variation for plant improvement.
Bannister, Maxwell and Smith, Quentin, "Electropenetography Reveals Altered Aphid Feeding Behavior Correlated with Differential Gene Expression in Wild Barley Hosts" (2020). All Zyzzogeton Presentations. 20.