1. Light Units 0 5 10 15 20 25 30 35 40 Auxin/HPHP/HPwater/HP Light Units 0 50 100 150 200 Auxin/HPHP/HPwater/HP Supplementary Figure S1 Expression of GSTF8::LUC but not CaMV35S::LUC construct is regulated by desensitization GSTF8::LUC (A) or 35S::LUC (B) transgenic lines were pretreated for 18 h with either 1  M auxin, 1mM H 2 O 2 (HP) or water, prior to treatment with 1mM H 2 O 2. The bioluminscence of individual seedlings was measure 6 h after the second treatment and plotted. The last column contains statistical analysis using all pair tukey-kramer at 0.05 significance. Non- overlapping circles represent significant differences between treatment. GSTF8::LUC 35S::LUC A B

2. 0 10501003006001000  M H 2 O 2 1 st Induction 2 nd Induction 1mM H 2 O 2 Only H 2 O 2 concentrations capable of inducing the GSTF8 promoter can activate desensitization Plates containing three rows of four-day GSTF8::LUC seedlings were pretreated with different concentrations of H2O2 14 h prior to 1mM H 2 O 2. For each treatment, 3mL was added to a 55 mm MS plate containing 50  M luciferin and decanted after 40 min. The bioluminescence was measured for each seedling 6 h after after 1st and 2nd treatment using a CCD camera. The purple images reflect the fluorescence of the chlorophyll, while the green represents the luminescence expression from the active GSTF8::LUC construct. Supplementary Figure S2

3. Supplementary Figure S3 Okadaic acid treatment does not induce the GSTF8 promoter Four day old GSTF8::LUC seedlings were treated with 1  M auxin, 1  M okadiac aicd (OA) or water for 40 min and the bioluminescence over a 19 h time course was measrued using a CCD camera. The average light units per seedling for each treatment, with standard errors, are presented.