Fig. 4.

S-acylation is necessary for the function of C4 in symptom determination during BSCTV infection. (A) Nicotiana benthamiana plants were inoculated with pCAMBIA1300-BSCTV-C4^WT-1.8copy (wild-type) or pCAMBIA1300-BSCTV-C4^C8S-1.8copy (C8 mutated from a cysteine to a serine) using different concentrations of Agrobacterium relative to OD₆₀₀. The leaves local to the inoculation site were photographed after 9 d. (B) The top-curling phenotype of N. benthamiana induced by infection with BSCTV. The plants were photographed 9 d after inoculation. Enlarged images of the shoot tips are shown for a better comparison. The top-curling symptom did not appear on the plants infected with BSCTV-C4^C8S even a long time after inoculation. (C) Levels of BSCTV in the newly emerged shoots of N. benthamiana plants were detected using PCR 9 d after inoculation. ACTIN (N. benthamiana) was used as a control. (D) Accumulation of BSCTV in Arabidopsis protoplasts was measured 0, 2, and 4 d after infection. The DNA was extracted and subjected to a DNA gel blot using the BSCTV genome as a probe. The plant genomic DNA was used as the loading control. dpi, days post-infection; WT, wild-type. The results in this figure are representative of at least three independent experiments.