Figure 1.

RNA Gel Blot Analysis of the DS9, PR-1, PR-2, PR-5, Actin, and GAPDH Genes in TMV- and Mock-Inoculated Tobacco Leaves after Temperature Shift.

Detached healthy leaves of 50-day-old Samsun NN and 70-day-old Samsun nn tobacco plants were inoculated with TMV (10 μg/mL) or buffer only (Mock), incubated at 30°C for 40 hr, and then shifted to 20°C at time 0.

(A) Leaves from Samsun NN tobacco plants were harvested at the indicated times after the temperature shift and used for total RNA extraction. Aliquots of 20 μg of total RNA per lane were fractionated by gel electrophoresis, transferred to nylon membranes, and successively subjected to hybridization with the indicated radioactively labeled probes after stripping the former probe. To standardize RNA loading, the blot was stained with methylene blue (rRNA). The 2.4-kb RNA represents the length of the DS9 gene.

(B) Relative intensity of DS9 transcripts as shown in (A). The amounts of DS9 transcript are expressed as a ratio with that present in the control sample (0 hr after the temperature shift of mock-inoculated leaves), which was set equal to 100%. Values are the mean ±sd from four independent experiments.

(C) Leaves from Samsun nn tobacco plants were harvested at the indicated times after the temperature shift and used for total RNA extraction. RNA gel blot hybridization was performed as described in (A), using the DS9 cDNA probe. The experiment was repeated twice with similar results. The 2.4-kb RNA represents the length of the DS9 gene.