Figure 2.

Defense metabolites associated with the lignin pathway and encoded by the pathway enzymes Defense metabolites are illustrated in orange, highlighting their biosynthesis routes in the pathway. The distribution of the metabolites is based on the current knowledge of their biosynthesis. Steps 1, 2, 3, and 4 are the same as in Figure 1. The proposed monolignol transport mechanisms (a–c) are also the same as in Figure 1.