Figure 11.

Needle puncture inoculation allows trafficking of G76A and G156A to all cell types in upper leaves. (A) RNA was collected from upper leaves of 10 plants 28 days after needle puncture inoculation with G76A and G156A. Linear PSTVd transcript (positive control, L) and RNA from mock inoculated plants (negative control, M) are indicated. Linear PSTVd migrates faster than the circular form that predominates in infected cells. Ribosomal RNA (loading control) was visualized by ethidium bromide staining. RNA blot is from Table 3, experiment 2 (of four). (B) In situ hybridization was performed with 12 μm transverse sections collected from upper N. benthamiana leaves 28 days after needle puncture inoculation with wild type PSTVd (WT), G76A, or G156A. Images for each are representative of >100 sections. Purple dots are viroid hybridization signals. uEp, upper epidermis; Pm, palisade mesophyII; Sm, spongy mesophyII; Ph, phloem. Bars = 100 μm.