Development of in vitro technique for elimination of Raspberry bushy dwarf virus

Raspberry bushy dwarf virus (RBDV) is one of the most common and harmful raspberry pathogens, significantly reducing yield of the crop and quality of berries. The efficiency of various methods for RBDV eradication in Malinovaya Gryada variety in vitro plant lets was compared. Thermotherapy, chemotherapy and cryotherapy, as well as combinations of these techniques, have been tested to eliminate RBDV. Thermotherapy of aseptic plants was carried out in a growth chamber at alternating temperatures (16 h at 38°C, light intensity 25 µmol•m-2•s-1 ; 8 h at 24-26°C, darkness) for two weeks. Chemotherapy was carried out by in vitro plant culture for 4 weeks on Murashige-Skoog medium with 30 mg/L of ribavirin. For cryotherapy of shoot tips, the PVS2 vitrification technique was used. In vitro plants were tested for viruses by multiplex TaqMan real-time PCR. It was found that thermotherapy and chemotherapy alone, as well as the combination of these treatments with cryotherapy, did not result in RBDV elimination. Only when chemotherapy was used in combination with thermotherapy, RBDV was not detected in 37.5% of in vitro plants. The highest percentage of RBDV-free plants was obtained using the combined technique: chemotherapy + thermotherapy + cryotherapy, while RBDV elimination was confirmed in 66.7% plants.