Our data suggests that the small RNAs that mediate RNA silencing (also called RNA interference or RNAi) are not required for systemic silencing or transgene methylation.  This argues against a popular model that small RNAs are the systemic silencing signal or the DNA methylation signal.

  Does it describe a new discovery or a new methodology that's useful to others?

No, not really, but it uses a unique feature of plants—the ability to graft one individual to another—to address a fundamental question concerning RNA silencing.

  Could you summarize the significance of your paper in layman's terms?  

RNA silencing is a fundamental genetic regulatory mechanism in plants and animals that also serves as a defense against nucleic acid invaders, such as viruses.  Understanding how this mechanism works and how viruses get around it will help us devise strategies to combat viral disease, among other things.  Our paper provides important new information about the workings of the HC-Pro viral suppressor of silencing and argues against a popular model about how RNA silencing spreads throughout the plant.

  How did you become involved in this research?  

My research area is to understand how plant viruses interact to cause synergistic disease.  During these studies, we found that a viral protein called HC-Pro mediates a whole class of synergistic diseases by interfering with RNA silencing.  HC-Pro has become an important tool to understand the mechanism of RNA silencing.