AN INFECTIOUS PLANT VIRAL VECTOR AND AN ARTIFICIAL BIPARTITE PLANT VIRAL VECTOR FOR GENE EXPRESSION OR VIRUS-INDUCED GENE SILENCING

摘要

We have developed a versatile plant viral vector system based on Alternanthera mosaic virus (AItMV), suitable for infection by agroinfiltration or in vivo T7 transcripts from the same clone; agroinfection is enhanced by coinfiltration of a T7 RNA polymerase construct. Variants adapted for efficient protein expression, or for virus-induced gene silencing (VIGS), are based on a specific amino acid substitution (L88P) in the triple gene block 1 (TGB l) protein affecting RNA silencing suppression. A bipartite delivery system developed for AItMV delivers replicase (RdRp) functions separately from movement and encapsidation (TGB and coat protein, CP) functions by agroinfiltration, resulting in precise recombination of RdRp and TGB-CP constructs in planta. The bipartite delivery system has potential for high throughput protein expression or VIGS with the appropriate TGBl variant, for hosts including Nicotiana benthamiana and Arabidopsis thaliana. Equivalent TGB l substitutions in other potexviruses also reduced RNA silencing suppression, demonstrated with Potato virus X.