Fig. 7

t-CA promotes the auxin response. a OE#1 dwarfism is partially rescued by indole-3-acetic acid (IAA) in a rosette growth response assay. Plants were grown on media supplemented with the denoted doses of IAA for 18 days. Pools of ten plants were measured and data are presented as mean ± SD (n ≥ 10). The significance of the difference between the treated and untreated plants for each line is shown (****, P < 0.0001; two-way ANOVA with Bonferroni’s multiple comparisons test). b t-CA enhances auxin signaling. Five-day-old plants expressing DR5::GUS in either Col-0 or 35S::VP16-IAA17mImII (VP16-IAA17) background were treated for 5 h with the denoted doses of NAA and t-CA. The GUS reactions were stopped upon visible accumulation of blue color in the NAA and t-CA co-treated seedlings (i.e., before blue color accumulation in the respective NAA-treated controls). Similarly, the GUS reactions were stopped upon visible accumulation of blue color in the t-CA treated 35S::VP16-IAA17mImII DR5::GUS seedlings (i.e., before blue accumulation in the untreated control). c Auxin resistant mutants (axr2–1, axr3–1 and arf7–1 arf19–1 (arf db.)) are insensitive whereas a line with increased auxin response (VP16-IAA17) is hypersensitive to 1 μM t-CA in a rosette growth response assay. The fresh weight (FW) of plants was measured in pools of ten plants after 18 days of growth. Data are presented as mean ± SD (n ≥ 8). ns, not significant; ****, P < 0.0001 (one-way ANOVA with Bonferroni’s multiple comparisons test). d Rosettes of plants grown on media supplemented with the denoted doses of t-CA for 21 days. e Piperonylic acid (PA) enhances expression of the DR5::GUS reporter in the 35S::VP16-IAA17mImII (VP16-IAA17) background. Five-day-old plants were treated for 5 h with the denoted doses of PA. The GUS reactions were stopped upon visible accumulation of blue color in the PA-treated 35S::VP16-IAA17mImII (VP16-IAA17) DR5::GUS seedlings (i.e., before blue accumulation in the untreated control)