Fig. 5.

Model of aphid defence regulation by benzoxazinoid metabolism in maize seedlings. Both synthesis and catabolism regulate the abundance of DIMBOA-glucoside. Genetic variation in the biosynthetic pathway affects DIMBOA-glucoside abundance (Butrón et al., 2010), and both Mo17 and B73 have a transposon insertion in Bx10c, which encodes a constitutively expressed DIMBOA-Glc catabolic enzyme (Meihls et al., 2013). DIMBOA-Glc is a precursor for DIMBOA, which is required to trigger callose formation and perhaps other aphid defence responses in maize.