Bioconversion of 5-deoxystrigol stereoisomers to monohydroxylated strigolactones by plants.

The bioconversion of 5-deoxystrigol (5DS) and 4-deoxyorobanchol (4DO), the simplest canonical strigolactones (SLs), into monohydroxylated SLs such as strigol, sorgomol and orobanchol was confirmed by administering of stable isotope-labeled substrates to hydroponically grown plants. Liquid chromatography-mass spectrometry analyses established that 5DS was stereoselectively converted into strigol and sorgomol by cotton () and Chinese milk vetch (), respectively. 4DO was converted into orobanchol by rice (). However, the red bell pepper (), red clover (), and pea () negligibly converted 4DO into orobanchol. The red bell pepper converted -4DO into 2',8-bis-sorgomol. These results suggest that some plants generate orobanchol without passing through 4DO.