Metabolism of plant sterols by nematodes
- Cite this article as:
- Chitwood, D.J. & Lusby, W.R. Lipids (1991) 26: 619. doi:10.1007/BF02536426
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Parasitic nematodes do not biosynthesize sterolsde novo and therefore possess a nutritional requirement for sterol, which must be obtained from their hosts. Consequently, the metabolism of phytosterols by plant-parasitic nematodes is an important process with potential for selective exploitation. The sterol compositions of several species of plant-parasitic nematodes were determined by capillary gas chromatography-mass spectrometry and compared with the sterol compositions of their hosts. Saturation of the phytosterol nucleus was the major metabolic transformation performed by the root-knot nematodesMeloidogyne arenaria andM. incognita and the corn root lesion nematode,Prytalenchus agilis. In addition to saturation, the corn cyst nematode,Heterodera zeae, dealkylated its host sterols at C-24. Because free-living nematodes can be cultured in sterol-defined artificial medium, they have been successfully used as model organisms for investigation of sterol metabolism in plant-parasitic nematodes. Major pathways of phytosterol metabolism inCaenorhabditis elegans, Turbatrix aceti andPanagrellus redivivus incleded C-24 dealkylation and 4α-methylation (a pathway unique to nematodes).C. elegans andT. aceti introduced double bonds at C-7, andT. aceti andP. redivivus saturated the sterol nucleus similarly to the plant-parasitic species examined. Several azasteroids and long-chain dimethylalkylamines inhibited growth and development ofC. elegans and also the Δ24-sterol reductase enzyme system involved in the nematode C-24 dealkylation pathway.
gas chromatography-mass spectrometry
nuclear magnetic resonance
relative retention time