ABA receptor agonist iCB is a novel synthetic abscisic acid (ABA) receptor agonist with broad-spectrum activation across the three receptor subtypes, has IC50 of 0.16 uM in seedling establishment inhibition assay.
iCB shows a significantly higher inhibition of germination than Cyanabactin (CB) and ABA in seeds.
iCB is active in inhibiting seedling establishment 7 days after sowing, iCB showed long-lasting effects, and iCB (2 uM) inhibits early seedling growth after 22 days.
Dimeric receptors (i.e., PYR1, PYL1, PYL2) appears more critical than monomeric ones to mediate the iCB-dependent inhibition in seedling establishment assays.
iCB is a broad-spectrum agonist with nanomolar affinity for receptor-phosphatase complexes.
iCB shows activity against dimeric and PYL4/PYL5 receptors, is more active than CB against subfamily I receptors, i.e., PYL8 and PYL9.
iCB binds with a higher affinity than ABA to clade III receptor-phosphatase complexes.