A Microinjection Method for Infecting the Planthopper Sogatella furcifera (Hemiptera: Delphacidae) with the Southern Rice Black-Streaked Dwarf Virus.

The southern rice black-streaked dwarf virus (SRBSDV) causes significant economic damage to rice crops. This virus is transmitted to rice plants by the planthopper Sogatella furcifera (Horváth) in a persistent, circular, and propagative manner. Researchers currently lack suitable methods for assaying the activity of SRBSDV in vitro and preserving the virus all year. We used a microinjection method to directly inject SRBSDV extracts into the hemocoel of S. furcifera nymphs. SRBSDV was subsequently detected by Reverse Transcription-Polymerase Chain Reaction in more than 56.7% of the insects after 5 d and 60% of healthy rice plants fed by these insects also became SRBSDV infected. Moreover, injecting planthopper with an extract of SRBSDV-infected rice plant that had been frozen at -80°C for 220 d caused 63.3% to become viruliferous. These results indicate that SRBSDV can be successfully transmitted to S. furcifera by microinjection, and that extracts of SRBSDV-infected rice plants frozen at -80°C for 220 d still contain sufficient active SRBSDV to infect S. furcifera. We provide a novel way to preserve SRBSDV all year by injecting S. furcifera with the SRBSDV extract.