ABCG2 and infection: Although coumarins are known to penetrate and diffuse through plant tissues via dual transport mechanisms and achieve long-distance movement through the xylem and phloem—accounting for the efficacy of exogenous Fraxetin within larch [46]—the spatiotemporal dynamics, chemical speciation (e.g., conjugation), and local concentrations at infection sites, as well as the specific interaction sites with fungal membrane proteins (e.g., ABC transporters) within the plant, remain inadequately defined.