The potyviral suppressor of RNA silencing confers enhanced resistance to multiple pathogens.
Helper component-protease (HC-Pro) is a plant viral suppressor of RNA silencing, and transgenic tobacco expressing HC-Pro has increased susceptibility to a broad range of viral pathogens. Here we report that these plants also exhibit enhanced resistance to unrelated heterologous pathogens. Tobacco mosaic virus (TMV) infection of HC-Pro-expressing plants carrying the N resistance gene results in fewer and smaller lesions compared to controls without HC-Pro. The resistance to TMV is compromised but not eliminated by expression of nahG, which prevents accumulation of salicylic acid (SA), an important defense signaling molecule. HC-Pro-expressing plants are also more resistant to tomato black ring nepovirus (TBRV) and to the oomycete Peronospora tabacina. Enhanced TBRV resistance is SA-independent, whereas the response to P. tabacina is associated with early induction of markers characteristic of SA-dependent defense. Thus, a plant viral suppressor of RNA silencing enhances resistance to multiple pathogens via both SA-dependent and SA-independent mechanisms.
Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
Gail J
GJ
Pruss
Christopher B
CB
Lawrence
Troy
T
Bass
Qingshun Q
QQ
Li
Lewis H
LH
Bowman
Vicki
V
Vance
D003546:Cysteine Endopeptidases / Q000096:biosynthesis / Q000235:genetics*; D017860:Nepovirus / Q000472:pathogenicity; D044742:Peronospora / Q000472:pathogenicity; D018515:Plant Leaves / Q000821:virology; D030821:Plants, Genetically Modified / Q000276:immunology / Q000821:virology; D034622:RNA Interference; D020156:Salicylic Acid / Q000032:analysis / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics* / Q000276:immunology / Q000821:virology; D014027:Tobacco Mosaic Virus / Q000235:genetics* / Q000472:pathogenicity; D014764:Viral Proteins / Q000096:biosynthesis / Q000235:genetics*
D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus; D020156:Salicylic Acid