Rational design and herbicidal activity of tenuazonic acid derivatives based on photosystem II D1 protein

Natural products are an important source for the development of herbicides. Tenuazonic acid (TeA) is a natural phytotoxin produced by phytopathogenic fungi that strongly inhibits photosystem II (PS II) by preventing electron flow from the primary quinone acceptor (QA) of PS II to the secondary quinone acceptor (QB), thereby directly disrupting the key chain of plant photosynthesis.

A series of TeA derivatives were rationally designed and synthesized based on the PS II D1 protein, and their herbicidal activities were evaluated. Compound C11 achieved > 90% control of Abutilon theophrasti and Portulaca oleracea at 37.5 g a.i. ha^-1, whereas atrazine achieved < 50% at the same rate. Meanwhile, compound C11 exhibited outstanding crop safety in cotton, peanut, wheat, corn, and rice at 300 g a.i. ha^-1 and performed better than atrazine. Furthermore, it was found to be less toxic to zebrafish embryos than atrazine and TeA. Molecular simulation analysis and chlorophyll fluorescence evaluation revealed that compound C11 exhibits a stronger binding affinity to the PS II D1 protein.

Compound C11, with excellent herbicidal activity and remarkable safety in crops and zebrafish embryos, was discovered, and it can be regarded as a potential lead compound for the development of a new type of PS II-inhibiting herbicide. © 2025 Society of Chemical Industry.