Figure 7.

Induction of ESR1 Expression by Cytokinin.

(A) RNA gel blot analysis in seedlings. Two-week-old Arabidopsis plants grown on MS medium were transferred onto MS medium containing various phytohormones. After 24 hr, total RNAs were prepared and analyzed on a gel. Ten micrograms of total RNA was loaded and hybridized to different cDNA probes. Mock, fresh MS medium without any phytohormones; ACC, 1-aminocyclopropane-1-carboxylic acid (50 μM); IAA, indole-3-acetic acid (2.5 μM). 2-ip was used at a concentration of 5 μM.

(B) Expression of ESR1 in response to cytokinin with or without 2,4-D pretreatment in root explants. Root segments were pretreated on MS medium with or without 2,4-D (2 μM) for 4 days (indicated as MS pretreatment or 2,4-D pretreatment, respectively) and then transferred onto MS medium containing the compound(s) indicated. After 12 hr of incubation, total RNAs were prepared. Ten micrograms of total RNA was loaded on each lane and hybridized to different cDNA probes. Concentrations were as follows: adenine, 50 μM; trans-zeatin, 5 μM; 2-ip, 5 μM; 6-benzyladenine (BA), 5 μM; kinetin, 5 μM.