siRNA biogenesis and advances in topically applied dsRNA for controlling virus infections in tomato plants

This study investigated a non-transgenic RNA interference approach for protecting tomato plants against viral infections. Topical application of dsRNA targeting the coat protein (cp) gene of Tomato mosaic virus (ToMV) resulted in dose-dependent and sequence-specific protection. High doses (200 and 400 µg/plant) achieved 60-63% resistance. Similar results were observed against Potato virus Y (PVY). Protection was rapid (lasting up to 4 days) but ineffective against the phloem-limited DNA virus Tomato severe rugose virus (ToSRV). Deep sequencing revealed that while long dsRNA persisted in treated leaves, it did not move systemically; however, dsRNA-derived siRNAs (21- and 22-nt) were detected in untreated leaves, demonstrating endogenous processing and transport.

Camila M. Rego-Machado, Erich Y. T. Nakasu, João M. F. Silva, Natália Lucinda, Tatsuya Nagata, Alice K. Inoue-Nagata