Figure 4.

Characterization of Arabidopsis RPL23aA- and RPL23aB-silencing mutants. A, The 10-d-old seedlings grown on basal media without or with 10 to 50 μm estradiol (noninduced and induced, respectively). Images shown are representative of T₃ transgenics expressing the RPL23aA- or the RPL23aB-silencing cassette (RPL23aA-ihp and RPL23aB-ihp, respectively) or the empty vector control (pER8-ihp). Misshapen leaves with a pointed morphology are indicated by arrowheads. B, The 13-, 18-, and 21-d-old pER8-ihp-2 and RPL23aA-ihp-4 grown on inductive media as above. Bar = 2 mm. C, Comparison of the first four leaves from 13-d-old pER8-ihp-2 and RPL23aA-ihp-4 T₃ transgenic seedlings grown on inductive media. Leaves are ordered chronologically (oldest to youngest) left to right. Bars = 2 mm. D, Abnormal leaf and root morphology of 18-d-old RPL23aA-ihp-4 transgenics grown on inductive media. A segment of root from an 18-d-old pER8-ihp-2 transgenic seedling is shown for comparison. Roots are stained with toluidine blue. Arrowheads point to lateral roots. E, Dark-field micrographs showing leaf venation of 14- to 18-d-old pER8-ihp-2 and RPL23aA-ihp-4 T₃ transgenic seedlings grown on inductive media and cleared with chloral hydrate. Shown are the first, second, and third leaves and the hypocotyl/petiole junction. Arrowhead shows bifurcation of midveins in the petiole of RPL23aA-ihp-4 transgenics. F, The 38- and 74-d-old (top and bottom, respectively) pER8-ihp-2 and RPL23aA-ihp-4 T₃ transgenic seedlings grown on inductive media. Arrowheads in top segments point to rosette flowering branches in RPL23aA-ihp-4 transgenics. Bars = 2 cm. G, qRT-PCR quantification of RPL23aA and RPL23aB transcript abundance in RPL23aA-ihp-1 to -5, RPL23aB-ihp-1 to -3, and pER8-ihp-2 to -4 T₃ Arabidopsis transgenic seedlings plated on inductive media. Vertical and horizontal hatched lines represent the ACT7 standardized level of RPL23aA and RPL23aB transcripts, respectively, in transgenic lines on inductive media normalized to the transcript level in noninduced wild-type seedlings (set to 1). Black bars represent SEM. Gray bar represents 100% of wild-type transcript abundance. Asterisks highlight the lines depicted in A to F. [See online article for color version of this figure.]