A rapid, sensitive and cost-efficient assay to estimate viability of potato cyst nematodes
2012
van den Elsen, S.J.J. | Ave, M. | Schoenmakers, N. | Landeweert, R. | Bakker, J. | Helder, J.
Potato cyst nematodes (PCN) are quarantine organisms, and they belong to the economically most relevant pathogens of potato worldwide. Methodologies to assess the viability of their cysts which can contain 200-500 eggs protected by the hardened cuticle of a dead female, are either time and labor intensive, or lack robustness. We present a robust and cost-efficient viability assay based on loss of membrane integrity upon death. This assay uses trehalose, a disaccharide present at a high concentration in the perivitelline fluid of PCN eggs, as a viability marker. Although this assay can detect a single viable egg, the limit of detection for regular field samples was higher, ~ ten viable eggs, due to background signals produced by other soil components. On the basis of thirty non-viable PCN samples from The Netherlands, a threshold level was defined (¿Atrehalose= 0.0094) below which the presence of more than ten viable eggs is highly unlikely (true for ~ 99.7% of the observations). This assay can easily be combined with a subsequent DNA-based species determination. As the presence of trehalose is a general phenomenon among cyst nematodes, this method can probably be used for, e.g., soybean, sugar beet and cereal cyst nematodes as well
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