Elimination of Apple stem grooving virus from 'Mansoo' pear (Pyrus pyrifolia L.) by an antiviral agent combined with shoot tip culture

In this study, in vitro-cultured 'Mansoo' pear (Pyrus pyrifolia L.) plants infected with Apple stem grooving virus (ASGV) were used for testing the efficiency of the virus elimination methods. The shoot tips cut from infected plants were treated by thermotherapy ($37^{\circ}C$), cold therapy ($4^{\circ}C$), chemotherapy with ribavirin, and combination of these methods. Treatment periods were 2, 4, and 8 weeks, and concentrations of ribavirin were 20 and $40mg{\cdot}L^{-1}$. The efficiency of ASGV elimination was evaluated by reverse transcription polymerase chain reaction. The shoot survival rate was the highest at 100% after cold therapy, chemotherapy, and combination of two methods, while the rate was the lowest at 33.3% after thermotherapy for 2 weeks. The shoot survival rate after chemotherapy decreased gradually as the treatment period was prolonged. The ASGV elimination rate was the highest at 100% after ribavirin treatment at a concentration of $40mg{\cdot}L^{-1}$ and combination of ribavirin treatment and thermotherapy for 2 weeks, whereas the ASGV elimination rate after cold therapy was the lowest at 16.7%. However, the efficiency of ASGV elimination was enhanced up to 43.3% by the combination of cold therapy and ribavirin treatment. The efficiency of ASGV elimination for all treatments was increased as the treatment period was prolonged. Based on these results, we suggest that ribavirin treatment at a concentration of $20mg{\cdot}L^{-1}$ for 4 weeks or at a concentration of $40mg{\cdot}L^{-1}$ for 2 weeks combined with shoot tip culture was efficient for the elimination of ASGV from pear.

항바이러스제 처리와 경정배양에 의한 배(Pyrus pyrifolia L.) '만수'의 Apple stem grooving virus 무병화

본 연구는 Apple stem grooving virus (ASGV)에 감염된 배 (Pyrus pyrifolia L.) '만수'의 기내배양 식물체를 이용하여 효과적인 배 바이러스 무병화 기술을 알아보고자 수행하였다. 식물체의 경정조직을 잘라 열처리($37^{\circ}C$), 한냉처리($4^{\circ}C$), 항바이러스제인 ribavirin을 단독 또는 복합처리하였다. 처리기간은 2, 4, 8주였으며 ribavirin 농도는 20과 $40mg{\cdot}L^{-1}$이었다. 바이러스 제거율은 Reverse transcription polymerase chain reaction 분석으로 확인하였다. 신초 생존율은 2주간 한냉처리, 항바이러스제 단독처리와 한냉처리와 항바이러스제가 복합처리된 그룹에서 100%로 높았고 열처리에서 33.3%로 가장 낮았다. 단독으로 ribavirin을 처리한 그룹은 처리기간이 길수록 신초 생존율이 감소하는 경향이었다. ASGV 제거율은 2주간 ribavirin $40mg{\cdot}L^{-1}$ 농도로 처리한 그룹과 열처리와 ribavirin을 복합처리한 그룹에서 100%로 높았다. 한냉처리한 그룹의 바이러스 제거율은 16.7%로 가장 낮았으나 한냉처리와 ribavirin을 복합처리한 그룹에서는 43.3%로 향상되었다. 모든 처리에서 처리기간이 길수록 바이러스 제거율은 증가하였다. 본 실험을 통해 배 ASGV 제거에는 경정배양과 더불어 항바이러스제인 ribavirin을 $20mg{\cdot}L^{-1}$ 농도로 4주간 처리하거나 $40mg{\cdot}L^{-1}$ 농도로 2주간 단독처리만으로도 효과적으로 무병화가 가능할 것으로 판단되었다.