Pale cyst nematode (Globadera pallida) cysts on potato roots
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Erosion of Potato Resistance to Pale Cyst Nematode

Globodera pallida: 

  • A regulated pest, pale cyst nematode was found in Idaho in 2006  
  • Three pathotypes of pale cyst nematode are known to occur in Europe: Pa1, Pa2, and Pa3.  
  • The pathotype of the Idaho population is Pa2/3. 

ZERO TOLERANCE IN THE US 

Pale cyst nematode (Globadera pallida) cysts on potato roots
Pale cyst nematode (Globadera pallida) cysts on potato roots

Resistance breeding challenges 

  • PCN is highly heterogeneous. Thus, multiple resistance sources need to be incorporated into breeding germplasm.  
  • Continuous use of resistant varieties imposes a strong selection pressure which increases the frequency of resistance-breaking populations. 

Eradication effort in U.S. 

  • Soil fumigation: 1,3-dichloropropene 
  • Resistance: No resistance to PCN is found in russet type potatoes, but breeders are developing resistance for US growers 

Resistant breaking populations 

  • PCN reproduction on resistant potato varieties due to multiple croppings with resistant varieties containing the same resistance source has been observed in Europe  
  • This caused genetic selection for stronger and/or more virulent PCN populations 
PCN reproduction on resistant potato varieties chart
PCN reproduction on resistant potato varieties due to multiple croppings with resistant varieties containing the same resistance source (Niere et al., 2014)
Breeding for nematode resistance in new potato varieties illustration
Breeding for nematode resistance in new potato varieties

Biology of progeny cysts from resistant potatoes 

There is a significant change in the behavior of PCN from these resistant clones, including:  

  • Less hatch  
  • Larger cysts  
  • Longer larvae 
Bita FactsheetDownload

References:

  • Beniers, J. E., Nöllen, Y., van Eck, H. J., & Schouten, H. J. (2019). Increased virulence of Globodera pallida during repeated rearing on different resistant potato cultivars explained by a simple model. Plant Pathology, 68(3), 445-453.  
  • Dandurand, L. M., Zasada, I. A., Wang, X., Mimee, B., De Jong, W., Novy, R., … & Kuhl, J. C. (2019). Current status of potato cyst nematodes in North America. Annual review of phytopathology, 57, 117-133. 
  • Fournet, S., Kerlan, M. C., Renault, L., Dantec, J. P., Rouaux, C., & Montarry, J. (2013). Selection of nematodes by resistant plants has implications for local adaptation and cross‐virulence. Plant pathology, 62(1), 184-193. 
  • Fournet, S., Eoche‐Bosy, D., Renault, L., Hamelin, F. M., & Montarry, J. (2016). Adaptation to resistant hosts increases fitness on susceptible hosts in the plant parasitic nematode Globodera pallida. Ecology and evolution, 6(8), 2559-2568. 
  • Jones, J. (2017). The Fascinating Biology of Potato Cyst Nematodes. Globodera Alliance Newsletter.  
  • Kort, J., Ross, H., Rumpenhorst, H. J., & Stone, A. R. (1977). An international scheme for identifying and classifying pathotypes of potato cyst-nematodes Globodera rostochiensis and G. pallida. Nematologica, 23(3), 333-339. 
  • Mwangi, J. M., Niere, B., Finckh, M. R., Krüssel, S., & Kiewnick, S. (2019). Reproduction and life history traits of a resistance breaking Globodera pallida population. Society of Nematologists (via Exeley Incorporated). 
  • Turner, S. J., Stone, A. R., & Perry, J. N. (1983). Selection of potato cyst-nematodes on resistant Solanum vernei hybrids. Euphytica, 32(3), 911-917. 
  • Turner, S. J. (1990). The identification and fitness of virulent potato cyst-nematode populations (Globodera pallida) selected on resistant Solanum vernei hybrids for up to eleven generations. Annals of applied Biology, 117(2), 385-397. 

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