Ribavirin targets sugar transporter 6 to suppress acquisition and transmission of rice stripe tenuivirus by its vector Laodelphax striatellus.

BACKGROUND Rice stripe tenuivirus (RSV) is one of the most destructive pathogens of rice and other cereal crops. The virus is transmitted by the small brown planthopper (SBPH,Laodelphax striatellus) in a circulative-propagative manner. Thus, blocking transmission by the insect vector would provide an effective strategy to prevent epidemic outbreaks of the disease. RESULTS In this study, we explored the effect of ribavirin on acquisition and transmission of the virus by specifically inhibiting the expression of sugar transporter 6 (LsSt-6), which was recently reported as a key vector component for RSV transmission. Ribavirin at the highest concentration tested (250 mu mol L-1) significantly reduced RSV acquisition and transmission efficiency by SBPHs through inhibiting LsSt-6 messenger RNA (mRNA) level. Survival of the model insectSpodoptera frugiperdacell line (Sf9) was 95.0 +/- 2.2 and 85.6 +/- 2.1% after exposure to 250 mu mol L(-1)ribavirin or 8-azaguanine, respectively. Further study confirmed that 250 mu mol L(-1)ribavirin also significantly reduced LsSt-6 mRNA and protein levels in Sf9 cells. However, 8-azaguanine did not significantly inhibit viral infectivity and LsSt-6 mRNA levels in SBPH or the Sf9 cell line. CONCLUSION This result provides evidence that ribavirin has the potential to disrupt LsSt-6 expression but not others like viral RNAs to prevent acquiring RSV, which leads to less viral accumulation in SBPH tissues and thereby lower transmission efficiency.