Strigolactone biosynthesis catalyzed by cytochrome P450 and sulfotransferase in sorghum

• Published in: The New phytologist Vol. 232; no. 5; pp. 1999 - 2010
• Main Authors: Yoda, Akiyoshi, Mori, Narumi, Akiyama, Kohki, Kikuchi, Mayu, Xie, Xiaonan, Miura, Kenji, Yoneyama, Kaori, Sato‐Izawa, Kanna, Yamaguchi, Shinjiro, Yoneyama, Koichi, Nelson, David C., Nomura, Takahito
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.12.2021; John Wiley and Sons Inc
• Subjects: Biosynthesis; Catalysis; Crop damage; Crop production; Cytochrome; Cytochrome P-450 Enzyme System - genetics; Cytochrome P450; Cytochromes; Cytochromes P450; Gene deletion; Germination; Heterocyclic Compounds, 3-Ring; Hydroxyl groups; Lactones; Metabolism; Mutants; Orobanche; Parasitic plants; Phelipanche; Plant Roots; Plant species; Proteins; root parasitic plants; Seed germination; Sorghum; Sorghum - genetics; Sorghum bicolor; Striga; strigolactone; Substrates; Sulfotransferase; Sulfotransferases; Sorghum bicolor; root parasitic plants; biosynthesis; Striga; cytochrome P450; sulfotransferase; strigolactone
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.17737

Summary Root parasitic plants such as Striga, Orobanche, and Phelipanche spp. cause serious damage to crop production world‐wide. Deletion of the Low Germination Stimulant 1 (LGS1) gene gives a Striga‐resistance trait in sorghum (Sorghum bicolor). The LGS1 gene encodes a sulfotransferase‐like protein, but its function has not been elucidated. Since the profile of strigolactones (SLs) that induce seed germination in root parasitic plants is altered in the lgs1 mutant, LGS1 is thought to be an SL biosynthetic enzyme. In order to clarify the enzymatic function of LGS1, we looked for candidate SL substrates that accumulate in the lgs1 mutants and performed in vivo and in vitro metabolism experiments. We found the SL precursor 18‐hydroxycarlactonoic acid (18‐OH‐CLA) is a substrate for LGS1. CYP711A cytochrome P450 enzymes (SbMAX1 proteins) in sorghum produce 18‐OH‐CLA. When LGS1 and SbMAX1 coding sequences were co‐expressed in Nicotiana benthamiana with the upstream SL biosynthesis genes from sorghum, the canonical SLs 5‐deoxystrigol and 4‐deoxyorobanchol were produced. This finding showed that LGS1 in sorghum uses a sulfo group to catalyze leaving of a hydroxyl group and cyclization of 18‐OH‐CLA. A similar SL biosynthetic pathway has not been found in other plant species.