S -Aryl Butenolide Thioacetates as Strigolactone Agonists: Mechanism-Guided Design for Weed Management and Crop Growth Regulation

Strigolactones (SLs) act as plant hormones regulating shoot architecture and as rhizospheric signals inducing parasitic weed germination. Herein, sulfur-containing SL agonists were designed and synthesized to explore their potential in weed management and crop growth regulation. A series of S -aryl butenolide thioacetates were prepared through a modular two-step synthetic route. Their biological activities were evaluated using Orobanche cumana seed germination assays, winter wheat tillering tests, and strawberry fruit development studies. Several compounds exhibited pronounced SL-like activity, including effective stimulation of parasitic seed germination or suppression of wheat tillering. Preliminary strawberry trials further indicated that certain analogues could promoted fruit ripening. Molecular docking with the AtD14 receptor suggests that arylthio substitution is compatible with the SL binding pocket and may introduce additional π–S interactions. These results identify S -aryl butenolide thioacetates as functional SL agonists and provide guidance for the development of SL-based plant growth regulators.