GC-MS analysis of hydrophobic root exudates of Sorghum and implications onthe parasitic plant Striga asiatica

Striga asiatica is a parasitic angiosperm that responds to germination stim ulants produced by host plants, including many grasses. GC-MS analyses of h ydrophobic root exudates of sorghum revealed the root exudates to be compos ed of fatty acids, resorcinol, and a series of structurally related hydroqu inones, three of which were previously unknown. High yields of resorcinol a nd the hydroquinone series were detected in sorghum. At least one of the hy droquinones induces germination in Striga, and the resorcinol is thought to stabilize the hydroquinones in the soil. The previously unknown series of hydroquinones offers insight into the possible biosynthesis of the componen ts of the exudate and their possible importance in initiating Striga germin ation.