title: Plant-mediated gene silencing restricts growth of the potato late blight pathogen Phytophthora infestans.
abstract: Phytophthora infestans is an oomycete that causes severe damage to potato, and is well known for its ability to evolve rapidly in order to overcome resistant potato varieties. An RNA silencing strategy was evaluated here to clarify if small interfering RNA homologous to selected genes in P. infestans could be targeted from the plant host to reduce the magnitude of the infection. As a proof-of-concept, a hairpin RNA (hp-RNA) construct using the GFP marker gene was designed and introduced in potato. At 72 hpi, a 55-fold reduction of the signal intensity of a corresponding GFP expressing P. infestans strain on leaf samples of transgenic plants, compared with wild-type potato, was detected. This suggests that an RNA interference construct in the potato host could be processed and target a transcript of the pathogen. Three genes important in the infection process of P. infestans, PiGPB1, PiCESA2, and PiPEC, together with PiGAPDH taking part in basic cell maintenance were subsequently tested using an analogous transgenic strategy. Out of these gene candidates, the hp-PiGPB1 targeting the G protein β-subunit (PiGPB1) important for pathogenicity resulted in most restricted disease progress. Further, Illumina sequencing of inoculated transgenic potato leaves revealed sRNAs of 24/25 nt size homologous to the PiGPB1 gene in the transgenic plants indicating post-transcriptional silencing of the target gene. The work demonstrates that a host-induced gene-silencing approach is functional against P. infestans but is highly dependent on target gene for a successful outcome. This finding broadens the arsenal of control strategies to this important plant disease.
authors: Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, SE-75007 Uppsala, Sweden Sultana.Jahan@slu.se.
authors: Sultana N
authors: SN
authors: Jahan
authors: Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, SE-75007 Uppsala, Sweden.
authors: Anna K M
authors: AK
authors: Åsman
authors: Department of Evolutionary Biology, Uppsala University, Uppsala, Sweden.
authors: Pádraic
authors: P
authors: Corcoran
authors: Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, SE-75007 Uppsala, Sweden.
authors: Johan
authors: J
authors: Fogelqvist
authors: Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, SE-75007 Uppsala, Sweden.
authors: Ramesh R
authors: RR
authors: Vetukuri
authors: Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center for Plant Biology, P.O. Box 7080, SE-75007 Uppsala, Sweden.
authors: Christina
authors: C
authors: Dixelius
mesh_terms: D060467:Disease Resistance / Q000235:genetics; D006790:Host-Parasite Interactions / Q000235:genetics*; D055750:Phytophthora infestans / Q000502:physiology*; D010935:Plant Diseases / Q000469:parasitology; D030821:Plants, Genetically Modified / Q000469:parasitology / Q000502:physiology; D034622:RNA Interference; D011198:Solanum tuberosum / Q000469:parasitology*
keywords: Late blight; Phytophthora infestans; RNA interference; oomycete; potato; small RNA.