The potato cyst nematodes (PCN) Globodera rostochiensis and G. pallida pose one of the greatest threats to potato crops worldwide and are subject to strict quarantine regulations in many countries. The identification of these Globodera species based on morphology may be ambiguous due to the variability of the main morphological features and the overlapping of the standard parameters in these two species; thus, confirmation via molecular methods is recommended. Multiplex PCR with species-specific primers (ITS5/PITSp4 + PITSr3) allows both species to be distinguished. However, despite the development of molecular identification methods, the morphological approach remains useful as a complementary diagnostic technique. In this work, we report results of morphological and molecular analyses that were carried out in two Globodera species from Portuguese potato fields. The average morphometric values of 40 cysts and 40 second-stage juveniles were generally within the expected ranges for G. pallida and G. rostochiensis with some variations noted. Molecular analysis with multiplex PCR confirmed the morphometric identification. The present results confirmed the occurrence of two potato cyst nematode species, G. rostochiensis and G. pallida. Surprisingly, the analysis of soils from Portuguese potato fields detected a greater number of samples infested with G. pallida, which is contrary to expectation as G. rostochiensis has been considered the most widespread species in Portugal. The distinction between the two species is therefore essential in order to detect their presence in the country with a view to re-evaluating the control measures implemented so far and adopting more effective practices.
Differentiation of Australasian potato cyst nematode (PCN) populations using the polymerase chain reaction (PCR).
New Zealand Journal of Crop and Horticultural Science25,
123-129. DOI: 10.1080/01140671.1997.9513998
DGAV (2015). Organismos de quarentena. Acções realizadas. Relatórios de 2014. Lisbon, Portugal, Direção-Geral de Alimentação e Veterinária.
Molecular and morphological exploration of a mixed population of two potato-parasitizing nematode species, Globodera rostochiensis and G. pallida.
3-6. DOI: 10.2478/s11687-014-0201-3
TirchiN.TroccoliA.FanelliE.MokabliA.MouhoucheF.De LucaF. (2016).
Morphological and molecular identification of potato and cereal cyst nematode isolates from Algeria and their phylogenetic relationships with other populations from distant their geographical areas.
European Journal of Plant Pathology146,
861-880. DOI: 10.1007/s10658-016-0965-z
Van de VossenbergB.VoogdJ.WestenbergM.KarssenG. (2014).
Comparison of three conventional PCR test (Bulman & Marshall, 1997) versions for the molecular identification of Globodera pallida and G. rostochiensis cysts and juveniles.
27-33. DOI: 10.1111/epp.12101