Feeding Responses of Rhopalosiphum padi (Homoptera: Aphidae) to Barley Yellow Dwarf Virus Resistant and Susceptible Barley Varieties

Abstract

The probing and feeding behavior of an important vector of barley yellow dwarf virus (BYDV), the bird cherry-oat aphid, Rhopalosiphum padi was electronically monitored on barley varieties with and without the Yd2 gene, a gene that imparts BYDV resistance to certain cereal cultivars. The presence of the Yd2 gene was shown to have no significant effect on the time elapsed to the first sieve element contact, total number of sieve element contacts, or duration of phloem sieve element ingestion by R. padi . Furthermore, aphid probing and feeding was not greatly affected by BYDV infection in susceptible plants. These data demonstrate that the mechanisms underlying BYDV resistance in plants with the Yd2 gene do not involve factors significantly influencing plant-aphid interactions that invoke alterations in aphid probing or feeding behavior. In addition, the number of sieve element contacts and duration of ingestion from sieve element cells by R. padi indicate that this aphid should be highly efficient in acquiring and transmitting the phloem-delimited BYDV to ‘California Mariout’ barley, with or without the Yd2 gene.