Ethylene quantification in three rhizobacterial isolates from Striga hermonthica-infested maize and sorghum

Volatiles from the headspace of three rhizobacteria (Pseudomonas sp. 4MKS8, Klebsiella oxytoca 10MKR7 and Enterobacter sakazakii 8MR5) isolated from sorghum and maize rhizospheres were analysed by gas chromatography and gas chromatography-mass spectrometry for ethylene. The ethylene released ranged from trace concentrations in Pseudomonas sp. 4MKS8, 72 nmoles/108 CFU/mL in K. oxytoca 10MKR7 to 210 nmoles/108 CFU/mL in E. sakazakii 8MR5. The level released by E. sakazakii 8MR5 was similar to the level required for stimulating suicidal germination in Striga seeds, suggesting the potential use of this rhizobacterium in the biological control of Striga spp.