Figure 4.

Morphological Phenotypes of TCV-Infected Di-17, Nö, and F₂ Plants from a Di-17 × NahG Nö Cross.

(A) TCV-inoculated leaves at 4 DPI. Both of the F₂ plants shown contain at least one allele of HRT. The HR⁺ F₂ plant lacks the nahG transgene, whereas the HR⁻ plant contains the nahG transgene, which leads to suppression of HR.

(B) The morphological phenotypes of the corresponding TCV-inoculated plants at 14 DPI. Except for the Di-17–resistant parent (R, resistant), the rest of the plants show severe crinkling of their leaves and stunted, drooping bolts (S, susceptible).

(C) This series shows systemic cell death induced by TCV in the corresponding TCV-infected susceptible plants. Uninoculated leaves were removed from the bolt at 14 DPI and stained with trypan blue. The leaves of the plants exhibiting disease symptoms show intensely stained areas of dead cells (marked by arrowheads), which are concentrated around the veins and gradually spread to the rest of leaf. Cell death was not evident in the uninoculated leaves of resistant Di-17 infected with TCV (left).