Effects of viral silencing suppressors on tobacco ringspot virus infection in two Nicotiana species.
This study investigated the effects of silencing suppressors derived from six different viruses (P1, P19, P25, HcPro, AC2 and 2b), expressed in transgenic Nicotiana tabacum and Nicotiana benthamiana plants, on the infection pattern of tobacco ringspot virus (TRSV) potato calico strain. In N. benthamiana, this virus produced an initial infection with severe systemic symptoms, but the infection was strongly reduced within a few weeks as the plant recovered from the infection. P25 and HcPro silencing suppressors effectively prevented recovery in this host, allowing continuous accumulation of the viral RNA as well as of the virus-specific small interfering RNAs, in the systemically infected leaves. In the P1-, P19-, AC2- or 2b-expressing transgenic N. benthamiana, the recovery was not complete. Susceptibility of N. tabacum to this virus was temperature sensitive. At lower temperatures, up to 25 degrees C, the plants became systemically infected, but at higher temperatures, the infections were limited to the inoculated leaves. In these preventative conditions, all silencing suppressor transgenes (except P25, which was expressed at very low levels) allowed the establishment of systemic infections. Very strong and consistent systemic infections were observed in HcPro- and AC2-expressing plants.
Siddiqui
Shahid Aslam
SA
Laboratory of Plant Physiology and Molecular Biology, University of Turku, FIN-20014 Turku, Finland.
Sarmiento
Cecilia
C
Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 19086 Tallinn, Estonia.
Kiisma
Mariliis
M
Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 19086 Tallinn, Estonia.
Koivumäki
Satu
S
Laboratory of Genetics, University of Turku, FIN-20014 Turku, Finland.
Lemmetty
Anne
A
MTT Agrifood Research Finland, FIN-31600 Jokioinen, Finland.
Truve
Erkki
E
Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 19086 Tallinn, Estonia.
Lehto
Kirsi
K
Laboratory of Plant Physiology and Molecular Biology, University of Turku, FIN-20014 Turku, Finland.
D003546:Cysteine Endopeptidases / Q000235:genetics; D020868:Gene Silencing; D016153:Genes, Suppressor; D005814:Genes, Viral / Q000235:genetics*; D008969:Molecular Sequence Data; D017860:Nepovirus / Q000472:pathogenicity / Q000502:physiology*; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000821:virology; D030821:Plants, Genetically Modified; D034741:RNA, Small Interfering / Q000378:metabolism; D013696:Temperature; D014026:Nicotiana / Q000235:genetics / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism; D014774:Virulence; D014779:Virus Replication
D034741:RNA, Small Interfering; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus