FIGURE 6.

Hop/Sti1-RNAi plants are PVY^N-tolerant. (A) Nicotiana tabacum cv. Samsun NN wild-type plant infected by PVY^N. Twelve days after mechanical inoculation, plants show severe infection symptoms including leaf deformation (left) and necrosis of stem and leaf veins (right). (B) Hop/Sti1-RNAi plants infected with PVY^N. Transgenic plants look healthy and do not show typical disease symptoms 12 days after inoculation. (C) PVY-CP ELISA. PVY^N titer was determined in infected wild-type and Hop/Sti1-RNAi plants. An asterisk indicates significance (Bonferroni-corrected student’s t-test, p-value: 1.89E– 02). Error bars represent the standard error. (D) Accumulation of viral RNA in infected wild-type and Hop/Sti1-RNAi plants. RT-PCR was used to amplify a 122-basepair fragment of the viral RNA encoding the coat protein (depicted by an arrow labeled CP). The amplicon could be detected in infected wild-type and transgenic plants both, but not in non-infected control plants. Values below depict the respective band intensities relative to the infected wild-type control.