scholarly journals Taxonomy, Morphological and Molecular Identification of the Potato Cyst Nematodes, Globodera pallida and G. rostochiensis

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 184
Author(s):  
John Wainer ◽  
Quang Dinh
Keyword(s):  
Life Cycle ◽  
Molecular Identification ◽  
Soil Sampling ◽  
Globodera Pallida ◽  
Potato Cyst Nematodes ◽  
Cyst Nematodes ◽  
Primary Focus

The scope of this paper is limited to the taxonomy, detection, and reliable morphological and molecular identification of the potato cyst nematodes (PCN) Globodera pallida and G. rostochiensis. It describes the nomenclature, hosts, life cycle, pathotypes, and symptoms of the two species. It also provides detailed instructions for soil sampling and extraction of cysts from soil. The primary focus of the paper is the presentation of accurate and effective methods to identify the two principal PCN species.

Observations on the life cycle of potato cyst nematodes, Globodera rostochiensis and G. pallida, on early potato cultivars

Nematology ◽  
2014 ◽  
Vol 16 (8) ◽  
pp. 937-952 ◽  
Author(s):  
Negin Ebrahimi ◽  
Nicole Viaene ◽  
Kürt Demeulemeester ◽  
Maurice Moens
Keyword(s):  
Life Cycle ◽  
Weather Conditions ◽  
Potato Cultivars ◽  
Globodera Pallida ◽  
Management Approach ◽  
Potato Cyst Nematodes ◽  
Base Temperature ◽  
Early Potato ◽  
Degree Days ◽  
Cyst Nematodes

Potato cyst nematodes (PCN) are the most economically important nematode pests of potato. Early harvesting is part of a preventive management approach for very early potato varieties. In Belgium, tubers are harvested before 20 June because it is assumed that no cyst formation occurs by that date. However, this assumption might not be valid any more because of climate change, the availability of new cultivars (with new traits), and the increasing prevalence of Globodera pallida. Therefore, pot, microplot and field trials were conducted to study the life cycle of PCN in early potato-growing conditions. The development of populations of G. pallida on three potato cultivars, Eersteling (susceptible to PCN), Première (resistant to G. rostochiensis) and Ambassador (partially resistant to G. pallida) and that of G. rostochiensis on cv. Eersteling was monitored in the growth chamber with simulation of field temperatures of the season. On cvs Eersteling and Première, second-stage juveniles (J2), males, females and cysts of G. pallida populations were found 28, 56, 63 and 77 days after infestation with cysts (DAI), respectively. The number of degree days (DD) for G. pallida to complete its life cycle using a base temperature of 4°C was calculated 450 DD4. On cv. Ambassador, females of G. pallida were never observed. J2, males, females and cysts of G. rostochiensis were detected 42, 70, 70 and 84 DAI, respectively. This species needed 398 DD6 at a base temperature of 6°C to complete its life cycle. Observations in two fields and in microplots under prevailing weather conditions in 2013 revealed that cysts of G. pallida and G. rostochiensis were formed on June 12, when the accumulated degree days were 463 DD4 and 401 DD6, respectively. Our observations show that both species of Globodera develop earlier than was assumed based on previous data. Therefore, harvesting based on the accumulated heat above the basal development temperature required by PCN species can replace the set harvest date.

scholarly journals Occurrence and molecular characterization of cyst nematode species (Globodera spp.) associated with potato crops in Colombia

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0241256
Author(s):  
Daniela Vallejo ◽  
Diego A. Rojas ◽  
John A. Martinez ◽  
Sergio Marchant ◽  
Claudia M. Holguin ◽  
...  
Keyword(s):  
Management Strategies ◽  
Nematode Species ◽  
Globodera Pallida ◽  
Rrna Gene ◽  
Potato Cyst Nematodes ◽  
28S Rrna ◽  
Cyst Nematodes ◽  
Nucleotide Substitutions ◽  
Internal Transcribed Spacer Region ◽  
The Status

Potato cyst nematodes (PCN) from the genus Globodera spp. cause major losses in the potato (Solanum tuberosum) industry worldwide. Despite their importance, at present little is known about the status of this plant pathogen in cultivated potatoes in Colombia. In this study, a total of 589 samples collected from 75 geographic localities in nine potato producing regions of Colombia (Cundinamarca, Boyacá, Antioquia, Nariño, Santander, Norte de Santander, Tolima, Caldas and Cauca) were assayed for the presence of potato cyst nematodes. Fifty-seven percent of samples tested positive for PCN. Based on phylogenetic analysis of the internal transcribed spacer region (ITS1-5.8S-ITS2) of the rRNA gene and D2-D3 expansion segments of the 28S rRNA gene, all populations but one were identified as Globodera pallida. Sequences of G. pallida from Colombia formed a monophyletic group closely related to Peruvian populations, with the lowest average number of nucleotide substitutions per site (Dxy = 0.002) and net nucleotide substitutions per site (Da = 0.001), when compared to G. pallida populations from Europe, South and North America. A single sample formed a well-supported subclade along with G. rostochiensis and G. tabacum from Japan, USA and Argentina. To our knowledge this is the first comprehensive survey of Globodera populations from Colombia that includes genetic data. Our findings on species diversity and phylogenetic relationships of Globodera populations from Colombia may help elucidate the status and distribution of Globodera species, and lead to the development of accurate management strategies for the potato cyst nematodes.

scholarly journals Study of European and Czech populations of potato cyst nematodes (Globodera rostochiensis and G. pallida) by RAPD method

2011 ◽  
Vol 50 (No. 2) ◽  
pp. 70-74 ◽  
Author(s):  
P. Sedlák ◽  
M. Melounová ◽  
S. Skupinová ◽  
P. Vejl ◽  
J. Domkářová
Keyword(s):  
Animal Species ◽  
Molecular Genetic ◽  
Globodera Rostochiensis ◽  
Globodera Pallida ◽  
Genetic Identification ◽  
Potato Cyst Nematodes ◽  
Cyst Nematodes ◽  
Genetic Dissimilarity ◽  
Solanaceous Plants ◽  
Molecular Genetic Identification

Potato cyst nematodes (PCN) are the big problem in worldwide planting of potatoes and another Solanaceous plants. Identification of individual pathotypes according to international scheme is very demanding but a very important part of the phytosanitary process to control these pests. Molecular genetic identification of different plant and animal species or individuals is a very interesting way at the present time and let’s hope that it will be important in future. This report presents results of the RAPD study of nine different real PCN populations. There were five Globodera rostochiensis populations and four G. pallida populations. Pathotypes Ro2, Ro2/3, Ro4, Ro5, Pa2 and Pa3 were from European populations; population Ro1 and X were of Czech provenance. Genetics variable of these populations was described by a set of six decameric primers (OPA 07, OPG 03, OPG 05, OPG 08, OPG 10 and OPG 13). Genetic dissimilarity was by Gel Manager for Windows evaluated. Detectable differences behind all populations were found and the dendrogram was compiled. The unknown population X was sorted into group of Globodera pallida species subgroup of Pa2 consequently.

scholarly journals Variability of D2/D3 segment sequences of several populations and pathotypes of potato cyst nematodes (Globodera rostochiensis, Globodera pallida)

2010 ◽  
Vol 46 (No. 4) ◽  
pp. 171-180 ◽  
Author(s):  
O. Douda ◽  
M. Zouhar ◽  
E. Nováková ◽  
J. Mazáková ◽  
P. Ryšánek
Keyword(s):  
Dna Analysis ◽  
Pcr Amplification ◽  
Globodera Rostochiensis ◽  
Globodera Pallida ◽  
Potato Cyst Nematodes ◽  
Cyst Nematodes ◽  
Routine Diagnostics ◽  
Pair Comparisons ◽  
Single Fragment ◽  
Direct Management

Potato cyst nematodes (Globodera rostochiensis, Globodera pallida) remain a key pest in the main potato growing regions of the Czech Republic. Due to difficult direct management and presence of diverse pathotypes attacking different potato cultivars the rapid and reliable diagnostics is of crucial importance. Currently, efforts are aimed at a description of different pathotypes based on DNA analysis. The main objective of this study was to evaluate the homogeneity of sequences of D2/D3 segments of the 28S rDNA gene obtained from 3 populations of G. rostochiensis and 5 populations of G. pallida and estimate their value for diagnostic purposes. PCR amplification yielded a single fragment of the length of 700 bp approximately in all populations. The alignment score of the vast majority of all pair comparisons of G. rostochiensis and G. pallida populations varied from 98 to 99. In total 14 point deletions and 3 substitutions were observed. The variability of D2/D3 segments of potato cyst nematodes is rather low and this DNA region can be used for diagnostics on a species level because more differences were found after comparing with G. tabacum and G. millefolii sequences obtained from Gene Bank; however the applicability of D2/D3 sequences to routine diagnostics of potato cyst nematodes could be complicated by its similarity to corresponding sequences of the nematode G. artemisiae.

Quantification of viable eggs of the potato cyst nematodes (Globodera spp.) using either trehalose or RNA-specific Real-Time PCR

Nematology ◽  
2014 ◽  
Vol 16 (10) ◽  
pp. 1219-1232 ◽  
Author(s):  
Johanna E. Beniers ◽  
Thomas H. Been ◽  
Odette Mendes ◽  
Marga P.E. van Gent-Pelzer ◽  
Theo A.J. van der Lee
Keyword(s):  
Real Time ◽  
Visual Inspection ◽  
Membrane Integrity ◽  
Globodera Pallida ◽  
Potato Cyst Nematodes ◽  
Original Sample ◽  
Rt Pcr ◽  
Cyst Nematodes ◽  
Pcr Assay ◽  
Field Samples

Two novel methods for the quantitative estimation of the number of viable eggs of the potato cyst nematodes (Globodera pallida and G. rostochiensis) were tested and compared with visual inspection. One is based on the loss of membrane integrity upon death and uses trehalose (a disaccharide) as a marker, the second test exploits the rapid degeneration of mRNA upon decease with a RNA-specific Real-Time Polymerase Chain Reaction (RT-PCR) assay. The viability of eggs in suspensions with different numbers of eggs was determined morphologically and was compared with both trehalose and elongation-factor-1-alpha (EF1α) mRNA measurements. The trehalose assay provided results that were close to those of the visual assessment using a microscope but only when samples contained low numbers of eggs. The lowest detectable value is 1.1 egg in the original sample and small differences in the number of viable eggs can be detected. Unfortunately, trehalose measurements reached a saturation limit at 1 cyst 10 μl−1; therefore, samples with nematode numbers above 262 eggs have to be diluted. The presence of dead cysts did not have a negative effect on the trehalose measurements. However, the use of egg suspensions instead of encysted eggs improved both the trehalose absorbance and the reliability of the measurements. When cysts were exposed to a treatment with allylisothiocyanate, the trehalose measurement detected the presence of more viable eggs than a hatching assay. The RT-PCR assay required a minimum of 30 eggs before detection occurred but can detect up to 8000 eggs in a 25 μl sample, which is an advantage when samples with high PCN infestations have to be processed. However, the confidence intervals (CI) of the RT-PCR assay are larger than those of the trehalose assay, which results in a high variation of single measurements. For example, at a density of 210 eggs in the original sample the 95% CI for the trehalose assay covers 191-228 eggs, and the 95% CI for the RT-PCR assay for G. pallida lies between 73 and 602 eggs and for G. rostochiensis between 59 and 745 eggs. Trials with field samples using both methods supported the laboratory tests. 95% of the field samples tested with the trehalose assay lie within the CI of the standard curve compared to 58% of the RT-PCR tested samples for G. pallida. The measurements of the field samples of G. pallida and G. rostochiensis populations using both methods resulted in larger numbers of viable eggs being detected compared to a hatching test. Neither of the investigated methods in their current state of development is optimal for use as a substitute for the visual inspection used in monitoring labs. The variance of the RT-PCR assay is too high if used for quantitative monitoring; the density range of eggs that can be detected using the trehalose assay is too small.

scholarly journals Morphological and molecular identification of the potato cyst nematodes Globodera rostochiensis and G. pallida in Portuguese potato fields

Nematology ◽  
2017 ◽  
Vol 19 (8) ◽  
pp. 883-889 ◽  
Author(s):  
Maria J. Camacho ◽  
Filomena Nóbrega ◽  
Arlindo Lima ◽  
Manuel Mota ◽  
Maria L. Inácio
Keyword(s):  
Multiplex Pcr ◽  
Molecular Identification ◽  
Diagnostic Technique ◽  
Nematode Species ◽  
Globodera Rostochiensis ◽  
Control Measures ◽  
Potato Cyst Nematodes ◽  
Cyst Nematodes ◽  
Widespread Species ◽  
Species Specific

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.

The effect of mycorrhization of potato roots on the hatching chemicals active towards the potato cyst nematodes, Globodera pallida and G. rostochiensis

Nematology ◽  
2004 ◽  
Vol 6 (3) ◽  
pp. 335-342 ◽  
Author(s):  
Aileen Ryan ◽  
Peter Jones
Keyword(s):  
Liquid Chromatography ◽  
Cyst Nematode ◽  
Globodera Pallida ◽  
Potato Cyst Nematodes ◽  
Cyst Nematodes ◽  
Potato Root ◽  
Potato Plants ◽  
Nitrogen Concentrations ◽  
Mycorrhizal Plants ◽  
Species Specific

AbstractComparison of potato root leachates (PRL) collected from the roots of mycorrhizal (using the mixed-isolate inoculum, Vaminoc) and non-mycorrhizal potato cv. Golden Wonder confirmed that mycorrhization caused a significant increase in hatching activity towards Globodera pallida but not G. rostochiensis. After fractionating the leachates by low pressure molecular exclusion/anion exchange liquid chromatography, several potato cyst nematode (PCN) species-specific hatching factors (HF) were found only in PRL from mycorrhizal plants. Leachate from mycorrhizal plants also contained more of several of those HF common to PRL from both mycorrhizal and non-mycorrhizal plants. Significantly more hatching factor stimulants (HS) active towards both PCN species were found in the PRL from mycorrhizal than from non-mycorrhizal plants; several HS were specific to mycorrhizal plants. No differences (quantitative or qualitative) were observed in hatching inhibitor (HI) levels between PRL from mycorrhizal and non-mycorrhizal plants. Mycorrhization of potato plants resulted in a 20% increase in carbon but a 48% decrease in nitrogen concentrations of the PRL compared to that from the non-mycorrhizal plants.

The effects of α-solanine and zinc sulphate on the behaviour of potato cyst nematodes Globodera rostochiensis and G. pallida

Nematology ◽  
2015 ◽  
Vol 17 (9) ◽  
pp. 1105-1111 ◽  
Author(s):  
Vincas Būda ◽  
Rasa Čepulytė-Rakauskienė
Keyword(s):  
Host Plants ◽  
Zinc Sulphate ◽  
Globodera Rostochiensis ◽  
Globodera Pallida ◽  
The Other ◽  
Potato Cyst Nematodes ◽  
Water Control ◽  
Cyst Nematodes ◽  
Second Stage ◽  
Testing Period

Two behavioural assays were carried out: one on the attraction of potato cyst nematodes (PCN), Globodera rostochiensis and G. pallida, to solanaceae-specific secondary metabolite α-solanine, the other on the effect of ZnSO4 (a compound known to suppress chemoreceptors). The first assay demonstrated that α-solanine was attractive to second-stage juveniles (J2) of PCN; G. pallida was attracted to concentrations of 10−4 M and 10−5 M, whereas G. rostochiensis was attracted to 10−5 M. Globodera pallida reacted faster than G. rostochiensis to the same concentration of α-solanine. As α-solanine is produced by host plants of PCN, this compound is attributed to kairomones. The response to α-solanine of nematodes pre-exposed to a 3 mM ZnSO4 solution was significantly suppressed compared to that of water control. The effect was observed throughout the whole testing period (30 min). This is the first evidence that both α-solanine and ZnSO4 can affect the behaviour of hatched J2 of PCN.

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