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The plant hormone abscisic acid (ABA) plays a crucial role during the plant life cycle as well as in adaptive responses to environmental stresses. The core regulatory components of ABA signaling in plants are the pyrabactin resistance1/PYR1-like/regulatory ABA receptors (PYLs for simplicity) comprise the largest plant hormone receptor family known. They act as negative regulators of members of the protein phosphatases type 2C family (PP2Cs). Due to the biological importance of PYLs, many researchers have focused on their genetic redundancy and consequent functional divergence. However, little is understood of their evolution and its impact on the generation of regulatory diversity. In this study, we identiﬁed positive selection and function divergency in PYLs through phylogenetic reconstruction, gene structure and expression pattern analysis, positive selection analysis, functional divergence analysis, and structure comparison. We found correlation of desensitization of PYLs with specific modifications in the molecular recognition domain with functional diversification. Hence, an interesting antagonistic coevolution mechanism is proposed, which results in the functional diversification of ABA receptor family proteins. We believe a compensatory evolutionary pathway may have occurred.
PMID: 31740933 [PubMed - as supplied by publisher]