Fig. 3.

Phytochrome inactivation by FR radiation down-regulates the expression of induced defenses. (A) Effect of FR on the induction of phenolic compounds in response to simulated herbivory (mechanical damage with addition of S. frugiperda oral secretions to the wounds). Soluble phenolic compounds were measured 72 h after elicitation. (B) Effect of FR on the induction of HEL in response to simulated herbivory. The same experiment as in (A) except that HEL transcript abundance was measured as the response variable 7 h after simulated herbivory, and expressed relative to the level detected in the Ambient × Control combination. Amb, ambient light; FR, FR added to ambient light to simulate the effect of neighbor proximity in a canopy of low-leaf area index. Thin bars indicate 1 SEM (n = 4 replicates, see Materials and Methods). The FR × Herbivory interaction is significant in both panels (P < 0.05); different letters indicate significant differences between treatment means. For comparison with the response in the phyB mutant, see Fig. S3.