Figure 2.

Expression patterns and auxin responsiveness of MP target genes IAA19 and IAA30. (A-C) 5 d after germination (DAG) hypocotyls expressing (A) MP::MP-GUS or (B, C) IAA19::GUS. (D-F) 5–6 DAG cotyledon petioles expressing (D) MP::MP-GUS or (E and F) IAA30::GUS. Tissues depicted in (C and F) were treated for 4h with auxin (10 μM indole-3-acetic acid) prior to GUS staining. Note that the expression patterns of IAA19 and IAA30 overlap with that of MP (A, B, D, and E) and are auxin inducible (compare C to B and F to E). 1701 basepairs of upstream non-coding sequence was used to generate the IAA30::GUS reporter. The IAA19::GUS reporter and GUS-staining protocol has been previously described.⁵ Bars: (A-C) 0.2 mm; (D-F) 0.5 mm.