Second-stage juvenile of the potato cyst nematode Globodera rostochiensis moving in site egg.
The juvenile perforates the egg-shell with its stylet (not visible) that enables it to break through the egg-shell. This process is known as “hatching”.
In cyst nematodes the second-stage juveniles that have developed in the female after fertilization, are protected by the old cuticula of the female that has tanned and hardened after the female died. Inside this so called cyst the juveniles dehydrate and become dormant, and go into diapause. In this state metabolic activity is almost zero and in this way they can survive for many years. This dormant state at least lasts for 9 month, and during this period the nematode is not able to hatch. In our lab we developed a method to circumvent this diapause (Janssen et. al., 1987, Neth. J. Pl. Path, 93: 107-113).
Inside the eggs a saccharide named trehalose is present that serves as a cryoprotectant to protect the juvenile from extreme cold and drought. In our lab we use this characteristic to store cyst nematodes indefinitely at -80°C (Folkertsma et. al. 1997., Fundam. appl. Nematol., 20 (3), 299-302.
After nine months, depending on the cyst population or batch, juveniles are able to hatch from the eggs under favorable conditions which are a temperature of 20°C, moisture and presence of the host plant. Compounds released by the host roots are thought to trigger the hatching process. Host root diffusate can be easily obtained, by growing roots in aqua culture. Considerable work has been done to discover which molecules play a role in hatching of cyst nematodes, not only with respect to understanding the mode of action of these molecules but also for their potential application in controlling cyst nematodes in the field.
Besides this, studies are being done to find suitable non-host Solanacea that release these molecules and can be used as a trap crop to reduce cyst nematode infestation in the field.