Figure 4.

Classification of the annotated signatory / discriminatory metabolites in extracts of sorghum plants responding to infection by B. andropogonis, according to the chemical classes (A; see Table 1) and primary/prominent functions in defence (B; see Section 3.1, Section 3.2, Section 3.3 and Section 3.4 for functions of some annotated metabolites). A total of 76 plant metabolites were putatively identified. (A): Illustrates the chemical diversity of metabolites potentially contributing to defence against B. andropogonis (flavonoids and hydroxycinnamic acids—two major classes). (B): Due to some metabolites possessing more than one function, grouping was based on the known primary/prominent role in plant defence.