Potent and Receptor-Selective Germination Inhibitor for Striga hermonthica

Striga hermonthica, a root parasitic weed that infests a diverse range of crops, germinates through the perception of host-derived strigolactones (SLs) with receptor protein ShHTL. The development of effective strategies to suppress Striga represents an urgent challenge in combating poverty and starvation in Africa. We conducted high throughput screening to identify inhibitors for SL receptor in Striga. Through the screening of 800 compounds against eight receptor proteins (ShHTL4-11), 22 compounds were discovered as the ShHTL antagonist. Striga germination assay revealed that one out of 22 compounds has inhibitory activity to SL-induced Striga germination. Structure-activity relationship study of the primary hit compound afforded the Striga germination modulator (SGM-3) with higher potency. In vitro binding assay demonstrated that SGM-3 selectively binds to ShHTL7 which is known as the dominant receptor for Striga seed germination. SGM-3 will contribute to the suppression of Striga infection and elucidation of the parasitization mechanism.