Our laboratory studies interactions between viroids their plant hosts, with the aim of designing strategies to control plant diseases. To do this, we employ site-directed mutagenesis, secondary-structure prediction, and various methods for studying RNA/protein interactions. Recently, we have identified interactions between Potato spindle tuber viroid
(PSTVd) RNA and host protein kinases. The relationship between these interactions and the cascade of gene induction pathways leading to pathogenesis is under investigation. We have also used a Potato Virus X
(PVX)-based virus vector to assist in the identification of nuclear targeting signals within the PSTVd molecule.
Tomato (cv. Rutgers) infected with a severe strain of PSTVd (right). We use this system to study the relationship between Potato spindle tuber viroid structure and viroid function, including replication, movement into the nucleus, and pathogenesis.