title: Effects of viral silencing suppressors on tobacco ringspot virus infection in two Nicotiana species.
abstract: 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.
authors.affiliation: Laboratory of Plant Physiology and Molecular Biology, University of Turku, FIN-20014 Turku, Finland.
authors.forename: Shahid Aslam
authors.initials: SA
authors.lastname: Siddiqui
authors.affiliation: Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 19086 Tallinn, Estonia.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Sarmiento
authors.affiliation: Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 19086 Tallinn, Estonia.
authors.forename: Mariliis
authors.initials: M
authors.lastname: Kiisma
authors.affiliation: Laboratory of Genetics, University of Turku, FIN-20014 Turku, Finland.
authors.forename: Satu
authors.initials: S
authors.lastname: Koivumäki
authors.affiliation: MTT Agrifood Research Finland, FIN-31600 Jokioinen, Finland.
authors.forename: Anne
authors.initials: A
authors.lastname: Lemmetty
authors.affiliation: Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, 19086 Tallinn, Estonia.
authors.forename: Erkki
authors.initials: E
authors.lastname: Truve
authors.affiliation: Laboratory of Plant Physiology and Molecular Biology, University of Turku, FIN-20014 Turku, Finland.
authors.forename: Kirsi
authors.initials: K
authors.lastname: Lehto
mesh_terms: 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
chemical_list: D034741:RNA, Small Interfering; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus