[Transgenic wheat expressing virus-derived hairpin RNA is resistant to Barley yellow dwarf virus]

An expression vector expected to induce RNA interference against Barley yellow dwarf virus (BYDV), which expressed a composite hpRNA with the dsRNA stem homologous of BYDV GPV replicase gene and the antisense RNA loop homologous of coat protein gene, was designed without marker gene. The vector was transferred into callus cells from wheat (Triticum aestivum L.) immature embryos by particle bombardment. To select the positive transformants as early as possible, a rapid PCR, which does not need extract wheat DNA instead of few leaves, was used at regeneration stage of plantlets. Totally 21 plants proved to contain alien sequence. Antivirus test with high dose infected virus revealed that, 9 plants showed low level of resistance to BVDV, 6 plants showed moderate resistance and 6 plants showed high level of resistance. Interestingly, both low and moderate levels of resistance plants were no symptoms when infected by viruses at low dose. It suggests the dose- dependent effect of the resistance mediated by hpRNA to BYDV-GPV.