Abstract

A host-induced gene-silencing strategy for controlling potato late blight is presented, a plant disease that conventionally requires regular application of fungicides at high rates.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 beta-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.

Keywords

Late blight; oomycete; Phytophthora infestans; potato; RNA interference; small RNA

Published in

Journal of Experimental Botany
2015, Volume: 66, number: 9, pages: 2785-2794
Publisher: OXFORD UNIV PRESS

SLU Authors

• Fogelqvist, Johan

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    
Associated SLU-program

Agricultural landscape
SLU Plant Protection Network
AMR: Fungus


UKÄ Subject classification

Agricultural Science


Publication identifier

DOI: https://doi.org/10.1093/jxb/erv094

Permanent link to this page (URI)

https://res.slu.se/id/publ/72277