Next-generation insect-resistant plants: RNAi-mediated crop protection

Plant-mediated RNA interference (RNAi) shows great potential in crop protection. It relies on plants stably expressing double-stranded RNAs (dsRNAs) that target essentialgenesinpestinsects.Practicalapplication of thisstrategyischallenging because producing sufficient amounts of stable dsRNA in plants has proven to be difficult to achieve with conventional transgenesis. In addition, many insects do not respond to exogenously applied dsRNAs, either degrading them or failing to import them into the cytoplasm. We summarize recent progress in RNAi-medi- ated insect pest control and discuss factors determining its efficacy. Expressing dsRNA in chloroplasts overcomes many of the difficulties previously encoun- tered. We also highlight remaining challenges and discuss the environmental and biosafety issues involved in the use of this technology in agriculture