Submitted to: Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 4, 2007
Publication Date: July 4, 2007
Citation: Pridannikov, M.V., Petelina, G.G., Palchuk, M.V., Masler, E.P., Dzhavakhiya, V.G. 2007. Influence of components of Globodera rostochiensis cysts on the in vitro hatch of second-stage juveniles. Nematology. 9(6):837-844.
Interpretive Summary: Plant-parasitic nematodes attack all crops of agricultural importance, causing over $10 billion in losses annually to U.S. farmers and nearly $100 billion worldwide. Serious problems facing growers include a lack of environmentally and economically acceptable control agents to reduce the spread of important nematode species. These problems make the discovery and design of novel control agents, based upon the nematodes’ own regulatory mechanisms, especially critical. One approach to discovering new means to control nematodes is to identify ways to disrupt their normal development and reproductive processes by using molecules that occur naturally inside the nematode. In this study, a team of Russian and ARS scientists report the discovery of small molecules in the potato cyst nematode that control egg hatching in this pest. The results are significant because they represent the first characterization of hatching regulators produced by the potato cyst nematode, and will lead to the discovery of similar molecules regulating reproduction in other plant-parasitic nematodes. Consequently, this information will be used by researchers in the agrochemical and agricultural biotechnology industries who are developing safe, selective methods for nematode control.
The effects of potato nematode Globodera rostochiensis cyst components on in vitro egg hatching were evaluated. Aqueous homogenates of eggs and cyst walls, and aqueous rinses of cyst walls and eggs were examined. Homogenates of cyst walls, or rinsates of either cyst walls or eggs, each significantly increased egg hatch (t = 0.05) by 5-fold over sterile distilled water controls. Cyst or egg homogenates induced significant (t = 0.05) increases (7.7-9-fold) in egg hatch over controls. These values represent approximately 24.8 to 29 percent of the 31-fold induction of egg hatch by potato root diffusate, routinely used to stimulate hatch in G. rostochiensis. The hatch inducing factor(s) in cyst homogenates was thermostable, and retained activity after repeated freezing and thawing. Filter fractionation of cyst homogenate localized activity between 0.5 and 5 kD, with no hatch inducing activity present above 5 kD. Apparent depression of hatch induction at high concentrations of unfractionated cyst homogenates suggests the presence of hatch inhibitors.