Fig. 5.

Silencing SABP2 expression blocks SAR development. (A) The size of primary lesions developed by TMV-inoculated control and SABP2-silenced plants (T₂ generation) was measured at 7 dpi. Seven days after the primary TMV infection, the upper previously uninoculated leaves received a secondary inoculation with TMV. The diameter of the secondary lesions was then measured 7 days after challenge infection. Each value represents the average size (in mm ± standard deviation) of 50 lesions per line. (B) Morphology of TMV-induced lesions in control and SABP2-silenced tobacco. The leaves were photographed 7 days after secondary infection with TMV. (C) RNA blot analysis of TMV MP and PR-1 transcript accumulation in control and SABP2-silenced T₂ lines. Total RNA was isolated from systemic leaves before (0 day) or 7 days after a secondary inoculation with TMV (*). After transfer, the membrane was hybridized with probes for the TMV MP and PR-1.