Nitro-Phenlactone, a Carlactone Analog with Pleiotropic Strigolactone Activities

Strigolactones (SLs) are novel phytohormones that shape plant architecture by inhibiting shoot branching and regulating root growth, besides their established functions in stimulating seed germination of root-parasitic weeds, such as Striga and Phelipanche species, and inducing hyphal branching in arbuscular mycorrhizal (AM) fungi (Al-Babili and Bouwmeester, 2015). Canonical SLs are divided into strigol- and orobanchol-like subfamilies with a typical structure consisting of a tricyclic (ABC-ring) and a monocyclic lactone (D-ring), which are connected by an enol ether bridge (Figure 1A and Supplemental Figure 1).