Analysis of Strigolactones, Germination Stimulants for Striga and Orobanche, by High-Performance Liquid Chromatography/Tandem Mass Spectrometry

A simple and rapid analytical method for strigolactones, germination stimulants for the root parasitic weeds witchweed (Striga spp.) and broomrape (Orobanche spp.), has been developed using high-performance liquid chromatography connected to tandem mass spectrometry (LC/MS/MS). The natural strigolactones (strigol, sorgolactone, orobanchol, and alectrol) were clearly separated and identified by LC/MS/MS. As low as 0.1 pg/μL of strigol and 0.5 pg/μL of sorgolactone could be quantified, whereas 1 pg/μL was needed for the quantification of orobanchol (S/N > 10). Using this method, it was found that red clover produces orobanchol and alectrol but not strigol. The roots of red clover seedlings were found to produce 13, 70, 58, and 65 pg of orobanchol/plant 1, 2, 3, and 4 weeks after germination, respectively. Keywords: LC/MS/MS; strigol; orobanchol; sorgolactone; parasitic weeds; germination stimulants; Striga spp.; Orobanche spp.