Construction of hairpin RNA structure inducing RNA silencing and evaluation of resistance derived by it against Grapevine Fanleaf Virus

The most efficient approach to control virus agents is the use of the resistant plant varieties. The RNA silencing-based resistance is the best way to establish the resistant plants against viruses. Grapevine fanleaf virus (GFLV) is one of the most destructive viral diseases of grapevines worldwide. In order to investigate the possibility of the resistance induction against GFLV using RNA-mediated induction of resistance, nucleotide sequence of two genes of GFLV was used to produce a hairpin construct. The construct was developed using intron and also the fragments in sense and antisense directions in front of 35S promoter in pGA482G. Agrobacterium tumefaciens was used to transform Nicotiana benthamiana plants. To evaluate resistance to GFLV after confirmation of transformation, the transgenic plants were mechanically inoculated with this virus. 10 days after virus inoculation, the inoculated plants showed various reactions including resistance, susceptibility and delay in symptom production. ELISA assay confirmed the absence of the virus in the resistant transgenic plants. No symptom was observed in these plants even a month after inoculation. The transgenic plants in which the virus was detected by ELISA reaction, mosaic symptom similar to that in wild type plants was appeared one week after inoculation. The results of this study showed that the developed construct containing a sequence of GFLV is efficient to establish the resistance to this virus and could be applied to produce the resistance in the different grape varieties.