Figure 2.
Expression of Ry sto leads to immunity of transgenic plants to PVY infection. (a) Illustration of ER ‐type response of PVY ‐inoculated leaves of Solanum tuberosum cv Russet Burbank plants expressing Ry sto . Four‐week‐old transgenic potato plants cv. Russet Burbank carrying construct 35S:Ry sto , and non‐transformed plants, were inoculated with PVYNTN . Two weeks after infection, chlorosis was observed on inoculated leaves of non‐transformed plants (right), whereas Ry sto transgenic plants (left) remained symptomless. (b) Ry sto expression completely blocks PVY spreading in transgenic potato plants. Four‐week‐old transgenic potato plants cv. Russet Burbank (upper graph) or Maris Piper (middle graph) carrying construct 35S:Ry sto , Maris Piper (lower graph) plants carrying Ry sto construct under the control of native 5′ and 3′ regulatory elements and non‐transformed plants were inoculated with PVYNTN . Three weeks after viral inoculation, mRNA was isolated from upper, non‐inoculated leaves. PVY RNA levels and expression of Ry sto were quantified using qPCR , relative to EF 1 and Sec3 reference genes, and expressed as means ± SD calculated from three biological replicates per plant line. One‐way ANOVA with Dunnett′s test was used for statistical analysis.