Figure 5.

Heatin application results in indole‐3‐acetonitrile (IAN) and indole‐3‐acetic acid (IAA) accumulation required for hypocotyl elongation.

(a) Relative Heatin effects on endogenous IAN and IAA levels. Two‐day‐old samples are shown as clear bars and 3‐day‐old samples are shown as striped bars. Horizontal dotted line indicates no difference between dimethyl sulphoxide (DMSO) and Heatin treatment. N = 4 replicates per treatment, each of 10 mg (fresh weight) seedlings. Asterisks indicate statistical significance, *P < 0.05, ***P < 0.001, determined by a Student’s t‐test.

(b) Dose–response curves of hypocotyl lengths of 8‐day‐old Col‐0 wild‐type seedlings grown on medium containing various concentrations of IAN in the presence (blue triangles) or absence (mock; grey squares) of Heatin (25 µm).

(c) Hypocotyl lengths of 8‐day‐old seedlings of Col‐0 wild‐type and various cyp79b2 and cypb79b3 and nitrilase1‐subfamily mutants, grown at 22°C (blue) and 27°C (green bars). Values are averages of (b) seven to eight independent repetitions of 15–68 seedlings, and (c) six to eight independent repetitions of 15–50 seedlings each. Error bars indicate SEM. Letters indicate significance groups (Tukey HSD post‐hoc test), where averages that do not share letters are significantly different from each other (P < 0.05). Note that these data provide independent confirmation for the observation that NIT1 and NIT2 contribute to thermomorphogenesis.