Figure 3.

Expression of CHRK1 mRNA. A, Tissue-specific expression. Each lane represents 50 μg of total RNA from roots (R), stems (S), leaves (L), or flowers (F). The amount of ethidium bromide-stained rRNA was shown to verify equal loading of RNA in each lane. B, Expression of CHRK1 mRNA during flower development. Fifty micrograms of total RNA of flowers from stage 1 to open flower stage, and from leaves (L) is represented in each lane. The five developmental stages are defined by bud size: <1 cm, stage 1; 1 to 2 cm, stage 2; 2 to 3 cm, stage 3; 3 to 4 cm, stage 4; open flower, stage OF. The K probe was used. C, Expression of CHRK1 mRNA in response to TMV infection. Fifty micrograms of total RNA was used in each lane. Lane 1 contains RNA from uninfected leaves; lane 2 contains RNA from leaves 1 d after infection; lane 3 contains RNA from leaves 3 d after infection. Duplicate membranes were hybridized with PR-1a probe as a control. The size of the PR1 transcripts is approximately 0.9 kb. The K probe was used. D, Expression of CHRK1 mRNA in response to fungal pathogen infection. Young tobacco plants were inoculated through roots with P. parasitica, which causes black shank disease in tobacco. Total RNA was prepared from leaves collected at 0, 1, 2, 3, and 8 d after infection. Fifty micrograms of total RNA was used in each lane. The K probe was used. Duplicate membranes were hybridized with chitinase probe as a control. The size of the chitinase transcripts is approximately 1.2 kb.