title: HC-Pro, a potyvirus RNA silencing suppressor, cancels cycling of Cucumber mosaic virus in Nicotiana benthamiana plants.
abstract: The mixed infection of Cucumber mosaic virus (CMV) and a potyvirus has been known to increase CMV titer in Nicotiana benthamiana plants, resulting in synergistic viral symptoms. We found that among three potyviruses--Potato virus Y (PVY), Turnip mosaic virus (TuMV), and Clover yellow vein virus (C1YVV)--synergistic effects on CMV (or a recombinant CMV vector) titers were most efficiently induced by a co-infection with PVY in N. benthamiana plants. In addition, the helper component-proteinase (HC-Pro) gene of PVY expressed by transgenic plants, which is a viral RNA silencing suppressor, was sufficient to cancel the cycling pattern of CMV titer, resulting in increased levels of overall CMV accumulation. Surprisingly, we found that the levels of CMV and the foreign protein expressed from the CMV vector were much higher in the HC-Pro-transgenic plants than the levels detected in the plants mixed-infected with CMV and PVY. The mechanism for canceling the cyclic infection of CMV by the HC-Pro protein alone is discussed in view of the interaction between RNA silencing and HC-Pro, as well as the possible involvement of the 3a protein.
authors.affiliation: Plant Molecular Technology Research Group, Research Institute of Genome-based Biofactory, National Institute of Advanced Industrial Science and Technology, 2-17-1-1 Tsukisamuhigashi Toyohira-Ku, Sapporo 062-8517, Japan.
authors.forename: Noriho
authors.initials: N
authors.lastname: Fukuzawa
authors.forename: Noriko
authors.initials: N
authors.lastname: Itchoda
authors.forename: Takeaki
authors.initials: T
authors.lastname: Ishihara
authors.forename: Kazunori
authors.initials: K
authors.lastname: Goto
authors.forename: Chikara
authors.initials: C
authors.lastname: Masuta
authors.forename: Takeshi
authors.initials: T
authors.lastname: Matsumura
mesh_terms: D017799:Cucumovirus / Q000254:growth & development*; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000821:virology; D017800:Potyvirus / Q000235:genetics / Q000254:growth & development*; D014026:Nicotiana / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus