Data quantification and normalization M. truncatula BSO treatment Control (h)GSH-depleted Inoculation with S. meliloti Time course (0, 12, 24,…, 96h) Time course (0, 12, 24,…, 96h) cDNA-AFLP analysis 6149 tags visualized Data quantification and normalization Group A: 299 nodulation regulated genes CVnod ≥ 0.4 Control/(h)GSH-depleted variance test p<0.05 Group B: 181 (h)GSH-regulated genes Figure S1: Experimental design and data analysis scheme for isolation of (h)GSH-regulated genes during the nodulation process. Group A: the Coefficient of Variance (CVnod) ≥ 0.4, was retained to select genes differentially expressed during the nodulation process. Group B : analysis of variance (P≤0.05), was performed to select genes affected by the (h)GSH depletion