Gene expression analysis of the genes associated with enzymes catalyzing serotonin biosynthesis. (A) A zoom-in view of the serotonin biosynthetic pathway. (B) Heat map of expression pattern of all cycling genes in the pathway with the gene ID and reaction of the pathway. Colored circles are used to identify individual reactions. (C) Biotic and abiotic stress induction of tryptophan biosynthetic genes based on data compiled in Genevestigator for rice. Expression data available for perturbations were filtered for significance level (p- value <0.05) and fold change (>2, based on gene in column with a yellow outline).