A Single Copy of Virus-Derived, Transgene-Encoding Hairpin RNA Confers BYDV Immunity

摘要

The PAV serotype o/Barley yellow dwarf virus (BYDV-PAV) is the most damaging virus of cereals worldwide. Natural resistance genes against the virus give inadequate control, and previous attempts to introduce synthetic resistance genes have been disappointing. The transformation of cereals with BYDV coat protein or polymerase genes has produced a few virus-resistant plants, but the resistance has been weak, unstable, or has failed to segregate as expected. In an attempt to generate barley with protection against BYDV, Golden Promise barley was transformed with a transgene that was designed to produce hairpin (hp)RNAfrom BYDV-PAV sequences. The majority of the resulting lines contained a single copy transgene insert and were rated as immune because the virus could not be detected in the challenged plants by ELISA nor recovered by aphid feeding experiments. In the field, BYDV-PAV is sometimes associated with the related luteovirus Cereal yellow dwarf virus (CYDV-RPV). When the transgenic plants were challenged with BYDV-PAV and CYDV together, the plants were susceptible to CYDV but immune to BYDV-PAV This shows that the immunity is sequence-specific and not broken down by the presence of CYDV. It also suggests that the immunity will be robust in thefield and very useful in minimizing losses in barley production due to BYDV-PAV.