A circular RNA vector for targeted plant gene silencing based on an asymptomatic viroid.

Gene silencing for functional studies in plants has been largely facilitated by manipulating viral genomes with inserts from host genes to trigger virus-induced gene silencing (VIGS) against the corresponding mRNAs. However, viral genomes encode multiple proteins and can disrupt plant homeostasis by interfering with endogenous cell mechanisms. To try to circumvent this functional limitation, we have developed a silencing method based on the minimal autonomously-infectious nucleic acids currently known: viroids, which lack proven coding capability.