Integrative Morphometric and Molecular Approach to Update the Impact and Distribution of Potato Cyst Nematodes Globodera rostochiensis and Globodera pallida (Tylenchida: Heteroderidae) in Algeria

Abstract

Morphological and molecular studies were conducted to characterize the specific identity of 36 isolates of potato cyst nematodes (PCNs) recovered from soil samples collected in several potato producing areas of Algeria. Morphometric data revealed that 44% of isolates contained Globodera pallida alone, 28% contained Globodera rostochiensis alone and 28% mixtures of the two species. Morphometric values of cysts and second-stage juveniles were generally distributed with slight differences in the expected ranges for both Globodera species. Inter- and intraspecific morphometric variability in nematode isolates was noted. Molecular analysis using conventional multiplex PCR with species-specific primers and TaqMan real-time PCR confirmed the morphological identification. In addition, the distribution of both potato cyst nematode species throughout various parts of the country was investigated. In the central areas, the isolates of G. pallida alone dominate, whereas isolates of G. rostochiensis alone are more frequent in the southern areas. In the eastern regions, mixed isolates are more representative. Most isolates examined in the western areas are mixtures of the two species or G. rostochiensis alone. Comparatively, G. pallida remains the most widely distributed species in its geographic range. This study confirms the presence of two PCN species, G. pallida and G. rostochiensis, in Algeria and provides additional information on their biogeographic distribution.

Development and Validation of a Loop-Mediated Isothermal Amplification Diagnostic Method to Detect the Quarantine Potato Pale Cyst Nematode, Globodera pallida

“…The detection of the target species within pools of non-target species was attempted because it was previously demonstrated that G. pallida and G. rostochiensis cohabit in mixed populations in potato fields [52,56]. Samples of pure G. pallida and pure G. rostochiensis were not used since the specificity had been previously demonstrated.…”

Predicting potential global distribution and risk regions for potato cyst nematodes (Globodera rostochiensis and Globodera pallida)

“…In reality, gPCN has been reported to occur together with pPCN in many areas. For example, 25% of the infested fields in England and Wales were detected with both nematode species, while the proportion was 28% in Algeria 7 , 8 . In Newfoundland (Canada), Portugal, and Kenya, gPCN was also accompanied by pPCN in some fields 11 , 14 , 16 .…”

“…Minnis et al were the first to report a detailed field survey of PCNs in the United Kingdom, which identified severe infestation of both gPCN and pPCN 7 . In recent years, countries in most global regions have confirmed the presence of PCNs; these included Portugal, Turkey, Algeria, Morocco, India, Indonesia, Australia, Colombia, Kenya, Canada and USA 8 – 17 .…”

Resisting Potato Cyst Nematodes With Resistance

“…The widespread presence of these nematodes in East Africa provides a contemporary example of the failure to prevent spread and the devastating consequences incurred by subsistence farmers who have become dependent on potato for their livelihoods (Mburu et al, 2020). Both species of PCN are also widespread in Algeria, the largest potato producer in Africa (Djebroune et al, 2021).…”