Development of ABA analogs that regulate the receptors function

Abstract

The physiological functions of abscisic acid (ABA) are triggered by interactions between PYR/PYL/RCAR receptors (PYL) and group-A protein phosphatases 2C (PP2C). PYL antagonists, chemical compounds, capable of disrupting these interactions would be valuable in investigating the regulatory mechanisms of ABA signaling, especially in plant systems lacking genetic resources. Based on the structural mechanism of the PYL-PP2C coreceptor system for ABA, we have generated 3'-modified ABA analogs, AS6, PAO4, and PAT3, and a 4'-modified ABA analog, PANMe, as PYL antagonists. These compounds bound PYL with an affinity comparable to that of ABA and inhibited ABA-induced PYL-PP2C interactions both in vitro and in vivo. Additionally, to facilitate the practical use of ABA in agricultural fields, we developed photostable ABA analogs, BP2A compounds series, in which the dienoic acid side chain of ABA was replaced with phenylacetic acid.