Structure-function analysis identifies highly sensitive strigolactone receptors in Striga

• Published in: Science (American Association for the Advancement of Science) Vol. 350; no. 6257; pp. 203 - 207
• Main Authors: Toh, Shigeo, Holbrook-Smith, Duncan, Stogios, Peter J., Onopriyenko, Olena, Lumba, Shelley, Tsuchiya, Yuichiro, Savchenko, Alexei, McCourt, Peter
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 09.10.2015; The American Association for the Advancement of Science
• Subjects: Amino Acid Sequence; Arabidopsis - genetics; Arabidopsis - metabolism; Binding; Biology; Catalytic Domain; Crystal structure; Flowers & plants; Fungi; Germination - drug effects; Heterocyclic Compounds, 3-Ring - metabolism; Heterocyclic Compounds, 3-Ring - pharmacology; Hormones; Lactones - metabolism; Lactones - pharmacology; Molecular Sequence Data; Molecules; Parasites; Phylogeny; Plant Growth Regulators - metabolism; Plant Growth Regulators - pharmacology; Plant Proteins - chemistry; Plant Proteins - classification; Plant Proteins - genetics; Plants (organisms); Pocket; Protein Structure, Secondary; Receptors; Receptors, Cell Surface - chemistry; Receptors, Cell Surface - classification; Receptors, Cell Surface - genetics; Seeds - genetics; Seeds - growth & development; Seeds - metabolism; Striga - genetics; Striga - growth & development; Striga - metabolism; Structure-Activity Relationship; Weeds
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aac9476

Strigolactones are naturally occurring signaling molecules that affect plant development, fungi-plant interactions, and parasitic plant infestations. We characterized the function of 11 strigolactone receptors from the parasitic plant Striga hermonthica using chemical and structural biology. We found a clade of polyspecific receptors, including one that is sensitive to picomolar concentrations of strigolactone. A crystal structure of a highly sensitive strigolactone receptor from Striga revealed a larger binding pocket than that of the Arabidopsis receptor, which could explain the increased range of strigolactone sensitivity. Thus, the sensitivity of Striga to strigolactones from host plants is driven by receptor sensitivity. By expressing strigolactone receptors in Arabidopsis, we developed a bioassay that can be used to identify chemicals and crops with altered strigolactone levels.