Department of Plant Sciences

Epigenetic control mechanisms: use of iRNA elements for genetic control, and applications of high throughput sequencing techniques.

Gene silencing and disease resistance

Our group is currently in transition between our old home in the Sainsbury Laboratory Norwich to our new base in the Plant Sciences Department. From autumn in 2007 until the summer of 2008 we will be split between Norwich and shared lab space in the department and, in the summer of 2008, we will move into a new laboratory on the top floor of the Botany School Building. 
See the plans

The two main topics of our work are linked by our long standing interest in the interactions between viruses and their hosts. The first topic involves protein-based innate immunity mechanisms in plants against pests and disease. In particular we are focusing on aspects of a molecular recognition process in which plants recognize the presence of a virus. Our aim in this area is to develop approaches to breeding or engineering of disease resistance in plants and to understand the evolutionary dynamics of host parasite interactions.

The second topic involves family of RNA-based processes collectively known asRNA silencing. The defining feature of these processes is the involvement of short RNA molecules that guide an Argonaute/Piwi protein to their target. We developed an interest in this process because it explains immunity and cross protection phenomena that have been known about in the virological literature for decades. The observation was that plants infected with a virus become resistant to secondary infection by the same or related viruses but not to distant or non relatives. We now know that the virus immunity and cross protection results from presence of short silencing RNAs that are derived from the viral genome. These RNAs then guide Argonaute so that it can destroy the RNA of secondarily inoculated viruses.

However, RNA silencing is more than targeted RNA degradation by Argonaute: in addition to RNA degradation there are effects at the DNA and chromatin level with a direct effect on transcription. Correspondingly the biological role of silencing extends beyond virus resistance: it protects the genome by silencing transposons, it influences chromosome structure and function and it regulates gene expression during growth, development and in response to external stimuli. We are also interested in the effect of silencing on natural variation within and between species and on epigenetic effects in evolution.