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Culturing and Screening the Plant Parasitic Nematode Ditylenchus dipsaci
Published on: January 31, 2022
Pectinases in Aqueous Extracts of Ditylenchus dipsaci
Journal of Nematology
|March 27, 2009
Summary
Onion-infecting Ditylenchus dipsaci nematodes produce enzymes that break down plant cell walls. These enzymes, endo-polygalacturonase (endo-PG) and endo-pectinmethyltranseliminase (endo-PMTE), macerate plant tissues, aiding nematode invasion.
Area of Science:
- Plant Pathology
- Nematology
- Biochemistry
Background:
- Ditylenchus dipsaci, a significant onion pest, infects plants by secreting enzymes.
- Understanding these enzymes is crucial for developing effective disease management strategies.
Purpose of the Study:
- To characterize the cell wall-degrading enzymes produced by Ditylenchus dipsaci.
- To investigate the enzymatic activities and maceration capabilities of nematode extracts.
Main Methods:
- Aqueous extracts from monoxenically cultured Ditylenchus dipsaci were prepared.
- Enzyme activity assays were performed using viscometry and specific substrates (sodium polypectate, pectin N.F.).
- Maceration tests were conducted on various plant tissues (potato, onion) at different pH levels.
Main Results:
- Extracts contained endo-polygalacturonase (endo-PG) and endo-pectinmethyltranseliminase (endo-PMTE).
- Endo-PG showed optimal activity at pH 4.0-4.2, while endo-PMTE was optimal at pH 8.5+, requiring CaCl2.
- Nematode extracts effectively macerated onion and potato tissues across a pH range of 4.2-6.2.
Conclusions:
- Ditylenchus dipsaci secretes potent cell wall-degrading enzymes, contributing to its pathogenicity.
- The identified enzymes facilitate tissue maceration, enabling nematode penetration and colonization.
