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SUMMARY:The contributions of RNA-dependent RNA polymerase 6 and alternativ
 e oxidase in resistance to potato virus X - Zheng Li
DTSTART:20120531T153000Z
DTEND:20120531T160000Z
UID:TALK36392@talks.cam.ac.uk
CONTACT:Suzy Stoodley
DESCRIPTION:RNA-dependent RNA polymerase 6 (RDR6) is a component of the an
 tiviral RNA silencing machinery. In Nicotiana benthamiana RDR6 is importan
 t in the maintenance of basal resistance against several viruses\, includi
 ng Potato virus X (PVX). Work in the Baulcombe group showed that RDR6 help
 s to limit PVX systemic movement and invasion of apical zone in infected p
 lants. Alternative oxidase (AOX) is the sole enzyme of the alternative res
 piratory pathway. It regulates reactive oxygen species in mitochondria and
  plays a role downstream of salicylic acid (SA) in resistance to viruses. 
 Previous work in my lab showed that altering alternative respiratory pathw
 ay capacity by either overexpressing AOX or expressing a mutant gene\, AOX
 -E\, affects basal and SA-induced resistance to PVX in N. benthamiana plan
 ts. It was concluded that changes in mitochondrial reactive oxygen species
  contributes to defensive signalling and the induction of resistance to vi
 ruses by SA and to the maintenance of basal resistance to PVX. Thus\, ther
 e are at least two defense mechanisms that contribute to the maintenance o
 f defense against PVX\, and perhaps other viruses. To further examine the 
 roles of RDR6 and AOX in resistance to viruses\, I generated double-transg
 enic N. benthamiana plants that have down-regulated RDR6 gene expression a
 nd that either overexpress AOX (to enhance alternative respiratory pathway
  capacity and down-regulate reactive oxygen species generation) or express
  AOX-E (to decrease alternative respiratory pathway capacity and increase 
 signaling mediated by reactive oxygen species). My studies so far have sho
 wn that RDR6-mediated resistance and the resistance mechanism(s) controlle
 d by AOX-regulated signalling are both important in resistance to PVX.
LOCATION:Department of Plant Sciences\, Large Lecture Theatre
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