FIGURE 1.

Hormone crosstalk in directing biotrophic, hemibiotrophic, and necrotrophic interactions. During trophic divergence, SA orchestrates both biotrophic and hemibiotrophic interactions, while JA/ET orchestrates both necrotrophic and hemibiotrophic interactions. By interacting with SA, JA/ET, and other hormones, auxin, CK, ABA, GA, BR, and SL as well as their important biosynthesis, transport and response genes, receptors, regulatory components, and transcription factors are all involved in directing trophic divergence, and their crosstalk are widely diversified across these three trophic interactions. Red upward triangle arrows are used to indicate positive regulators for host immunity, and blue downward triangle arrows for negative regulators for host immunity in each specific trophic interaction. Black triangle arrows are denoted for positive regulations in the pathway, while black round arrows for negative regulations in the pathway. Question marks designate potential regulations that require further investigations. Trophic divergence by different hormones are separated by horizontal dotted lines, while different regulatory modules within a trophic interaction are separated by vertical dotted lines.