Potato Cyst Nematode Globodera Pallida Research Articles

A receptor for dual ligands governs plant immunity and hormone response and is targeted by a nematode effector

In this study, we show that the potato (Solanum tuberosum) pattern recognition receptor (PRR) NEMATODE-INDUCED LEUCINE-RICH REPEAT (LRR)-RLK1 (StNILR1) functions as a dual receptor, recognizing both nematode-associated molecular pattern ascaroside #18 (Ascr18) and plant hormone brassinosteroid (BR) to activate two different physiological outputs: pattern-triggered immunity (PTI) and BR response. Ascr18/BR-StNILR1 signaling requires the coreceptor potato BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED RECEPTOR KINASE 1 (StBAK1) and perception of either ligand strengthens StNILR1 interaction with StBAK1 in plant cells. Significantly, the parasitically successful potato cyst nematode (Globodera pallida) utilizes the effector RHA1B, which is a functional ubiquitin ligase, to target StNILR1 for ubiquitination-mediated proteasome-dependent degradation, thereby countering Ascr18/BR-StNILR1-mediated PTI in potato and facilitating nematode parasitism. These findings broaden our understanding of PRR specificity and reveal a nematode parasitic mechanism that targets a PTI signaling pathway.

The potato RNA metabolism machinery is targeted by the cyst nematode effector RHA1B for successful parasitism.

The potato (Solanum tuberosum) cyst nematode Globodera pallida induces a multinucleate feeding site (syncytium) in potato roots as its sole source of nutrition. Here, we demonstrate that the G. pallida effector RING-H2 finger A1b (RHA1B), which is a functional ubiquitin ligase, interferes with the carbon catabolite repression 4 (CCR4)-negative on TATA-less (NOT) deadenylase-based RNA metabolism machinery that regulates syncytium development in G. pallida-infected potato. Specifically, RHA1B targets the CCR4-associated factor 1 (CAF1) and StNOT10 subunits of the CCR4-NOT complex for proteasome-mediated degradation, leading to upregulation of the cyclin gene StCycA2 involved in syncytium formation. The StCAF1 subunit of CCR4-NOT recruits the RNA binding protein StPUM5 to deadenylate StCycA2 mRNA, resulting in shortened poly-A tails of StCycA2 mRNA and subsequently reduced transcript levels. Knockdown of either subunit (StCAF1 or StNOT10) of the CCR4-NOT complex or StPUM5 in transgenic potato plants resulted in enlarged syncytia and enhanced susceptibility to G. pallida infection, which resembles the phenotypes of StCycA2 overexpression transgenic potato plants. Genetic analyses indicate that transgenic potato plants overexpressing RHA1B exhibit similar phenotypes as transgenic potato plants with knockdown of StNOT10, StCAF1, or StPUM5. Thus, our data suggest that G. pallida utilizes the RHA1B effector to manipulate RNA metabolism in host plants, thereby promoting syncytium development for parasitic success.

Lure and starve: Host root exudates to suppress field populations of cyst nematodes

Plant parasitic nematodes are a burden to global food security, accounting for substantial yield losses in agricultural production worldwide. Increasing concerns over the environment and health issues have led to diminishing control options at the disposal of agricultural producers. Lure and starve, a strategy that is based on stimulating hatching of second stage juveniles (J2) of some cyst forming plant parasitic nematodes in the absence of their host plant seems a promising approach to maintain sustainability in crop production. Here we examined in-situ hatching of encysted eggs of the potato cyst nematode Globodera pallida and the carrot cyst nematode Heterodera carotae following exogenous applications of host root exudates in repeated field experiments during autumn and spring seasons. Population densities (viable J2 g−1 of soil) were assessed prior and post-application of root exudates. Results showed hatching induction of up to 83 % for G. pallida and 54 % for H. carotae in field plots drenched with their respective host root exudates. Spring season experiments were characterised by limited soil moisture and did not reduce nematode population densities for G. pallida. The potential for host root exudates in suppressing field population of cyst nematode in lure and starve strategies looks promising for both cyst nematode species investigated.

Characterisation and mapping of a Globodera pallida resistance derived from the wild potato species Solanum spegazzinii

Key messageA new resistance locus acting against the potato cyst nematode Globodera pallida was mapped to chromosome VI in the diploid wild potato species Solanum spegazzinii CPC 7195.The potato cyst nematodes (PCN) Globodera pallida and Globodera rostochiensis are economically important potato pests in almost all regions where potato is grown. One important management strategy involves deployment through introgression breeding into modern cultivars of new sources of naturally occurring resistance from wild potato species. We describe a new source of resistance to G. pallida from wild potato germplasm. The diploid species Solanum spegazzinii Bitter accession CPC 7195 shows resistance to G. pallida pathotypes Pa1 and Pa2/3. A cross and first backcross of S. spegazzinii with Solanum tuberosum Group Phureja cultivar Mayan Gold were performed, and the level of resistance to G. pallida Pa2/3 was determined in progeny clones. Bulk-segregant analysis (BSA) using generic mapping enrichment sequencing (GenSeq) and genotyping-by-sequencing were performed to identify single-nucleotide polymorphisms (SNPs) that are genetically linked to the resistance, using S. tuberosum Group Phureja clone DM1-3 516 R44 as a reference genome. These SNPs were converted into allele-specific PCR assays, and the resistance was mapped to an interval of roughly 118 kb on chromosome VI. This newly identified resistance, which we call Gpa VIlspg, can be used in future efforts to produce modern cultivars with enhanced and broad-spectrum resistances to the major pests and pathogens of potato.

Unmanned Aerial Vehicle (UAV) for Detection and Prediction of Damage Caused by Potato Cyst Nematode G. pallida on Selected Potato Cultivars

High population densities of the potato cyst nematodes (PCN) Globodera pallida and G. rostochiensis cause substantial yield losses to potato production (Solanum tuberosum) due to the delay caused to tuber formation by the retardation of plant growth. It requires meticulous estimation of the population densities by using soil sampling and applying the right combination of nematode management to deal with the PCN problem. This study aims to assess the use of an unmanned vehicle (UAV) in detecting and estimating the effect of ranges of densities of a PCN, G. pallida, on four cultivated potato cultivars with resistance to PCN in a naturally infested potato field in The Netherlands. First, the initial population density (Pi) of G. pallida was estimated by using an intensive sampling method of collecting about 1.5 kg of soil per m2 from the center of each 3 × 5 m plot. At harvest, the fresh tuber yield of the potato cultivars (Avarna, Fontane, Sarion, and Serresta) were assessed. The Seinhorst yield loss model was used to investigate the relationship between Pi and fresh tuber yield. Secondly, the spatial data of UAV with optical and thermal sensors were analyzed to find any relationship between Pi and UAV indices. By using the classical yield loss model, all four cultivars were found to be affected by Pi with a relative minimum fresh tuber yield m, which ranged from 0.26 to 0.40. The maximum fresh tuber yield varied from 49.48 to 80.36 tons (ha)−1. The density at which the fresh tuber yield started to deteriorate was in the range of 0.62–2.16 eggs (g dry soil)−1. A regression was observed between Pi, and all UAV indices in a similar pattern to that of the fresh tuber yield by using the Seinhorst yield loss model, except for the cultivar Avarna for the two UAV indices (NDRE and NDVI). Unlike the tolerance limit, the relative minimum values of the UAV indices—except the chlorophyll index—differ when compared among each other and when compared with that of the fresh tuber yield within the same cultivar. This indicates that all indices can be useful for detection and decision making for statutory purposes but not for estimating damage (except the chlorophyll index).

A Novel Rhabdovirus Associated with the Idaho Population of Potato Cyst Nematode Globodera pallida.

Globodera pallida, a potato cyst nematode (PCN), is a quarantine endoparasitic pest of potato (Solanum tuberosum) in the US due to its effects on yield and quality of potato tubers. A new rhabdovirus, named potato cyst nematode rhabdovirus (PcRV), was revealed and characterized in the G. pallida populations collected in Idaho through use of high-throughput sequencing (HTS) and RT-PCR and found to be most closely related to soybean cyst nematode rhabdovirus (ScRV). PcRV has a 13,604 bp long, single-stranded RNA genome encoding five open reading frames, including four rhabdovirus-specific genes, N, P, G, and L, and one unknown gene. PcRV was found present in eggs, invasive second-stage juveniles, and parasitic females of G. pallida, implying a vertical transmission mode. RT-PCR and partial sequencing of PcRV in laboratory-reared G. pallida populations maintained over five years suggested that the virus is highly persistent and genetically stable. Two other Globodera spp. reproducing on potato and reported in the US, G. rostochiensis and G. ellingtonae, tested negative for PcRV presence. To the best of our knowledge, PcRV is the first virus experimentally found infecting G. pallida. Based on their similar genome organizations, the phylogeny of their RNA-dependent RNA polymerase domains (L gene), and relatively high identity levels in their protein products, PcRV and ScRV are proposed to form a new genus, provisionally named "Gammanemrhavirus", within the family Rhabdoviridae.

Volatile Organic Compounds from a Lichen-Associated Bacterium, Paenibacillus etheri, Interact with Plant-Parasitic Cyst Nematodes.

Healthy food is one of the major challenges to develop in this century. Plant-parasitic nematodes cause significant damage to many crops worldwide and till now, the use of chemical nematicides is the main means to control their populations. These chemical products must be replaced by more environmental-friendly control methods. Biocontrol methods seem to be one promising option, and the number of biopesticides derived from living organisms has increased in the last decades. To develop new plant protection products, we have decided to combine our skills in natural products chemistry and nematology and to focus on the lichen microecosystem as underexploited ecological niches of microorganisms. We present herein the potential of lichen-associated bacterial suspensions from Paenibacillus etheri as nematicides against the beet cyst nematode Heterodera schachtii and the potato cyst nematode Globodera pallida, in particular the effects of volatile organic compounds (VOCs) produced by the bacteria. A solid phase micro-extraction method associated to gas chromatography-mass spectrometry analysis of 14 day cultures was used to analyze these VOCs in order to identify the main produced compounds (isoamyl acetate and 2-phenylethyl acetate) and to evaluate them on the nematodes.

First detection of the potato cyst nematode (Globodera rostochiensis) in a major potato production region of China.

The potato cyst nematodes (PCN) Globodera rostochiensis and Globodera pallida are the very important quarantine nematode pests of potato [Stone 1973]. Both species cause serious potato tuber yield losses. These species are subjected to strict quarantine regulations in many countries (EPPO 2017). G. rostochiensis was detected in Sichuan and Yunnan province, China in 2022 (Jiang et al. 2022). A survey for cyst nematodes in potato fields was conducted in Guizhou Province from 2018 to 2020. A total of 200 samples, including roots and soil, were collected from 40 potato fields in Hezhang (N27 06.145, E104 39.153) and Weining (N26 50.541, E104 09.885) counties in Guizhou Province, China. The Cobb decanting and sieving method was used to isolate cysts and J2s from the soil samples (Southey 1986). The potato roots were stained with acid fusion to observe cyst development. Morphological and molecular analyses indicated that 27 (13.5%) of the samples contained G. rostochiensis. The cyst density ranged between 1-85 cysts per 100 cm3 of soil and a mean density was 15 cysts per 100 cm3 soil. The smoothly rounded cysts were in brown and golden color, and the terminal cone was absent and circumfenestrate. The key morphometrics of cysts (n=20) were 695 ± 26 (685-757) μm in length excluding neck and 690 ± 30 (668 to769) μm in width; the number of cuticular ridges between anus and vulval fenestra was 16.3 ±2.1 (14 to 18); fenestral length was 15.1 ± 2.1 μm (13.18 to 19.27); distance from anus to the edge of fenestra was 61.12 ± 8.9 (49.22 to76.27) μm; and Granek's ratio was 4.54 ± 0.8 (3.97-5.26). The key morphometrics of J2 (n = 20): 468.0 ± 20.1 (427 to - 521) μm in body length, 20.58 ± 0.7 (20.2 to 21.8) μm in stylet length, 43.9 ± 5.6 (40.3 to 53.9) μm in tail length, and 23.1 ± 1.8 (21.77 to 25.32) μm in hyaline region length. The cyst and J2 morphologies were consistent with those of G. rostochiensis (Subbotin et al. 2010, EPPO 2017). Genomic DNA was isolated from cysts (n=20). DNA extraction was performed in a volume of 20 μl containing 3 μl 10× PCR buffer, 3 μl Proteinase K (600 μg μl-1), 14 μl distilled water and a single cyst was added and ground in an ice bath as described by Ou et al. (2008). The internal transcribed spacer (ITS) regions were amplified using the universal primers: rDNA1 (5'-TTGATTACGTCCCTGCCCTTT-3') and rDNA2 (5'-TTTCACTCGCCGTTACTAAGG-3') (Fleming 1998 ), and the 28S rDNA-D2/D3 regions were amplified using the primers: D2A (5´-ACAAGTACCGTGAGGGAAAGTTG-3´) and D3B (5´-TCGGAAGGAACCAGCTACTA-3´) (Subbotin et al. 2006). After the brackets at the beginning and end of the sequences were closed-up, the ITS rDNA sequences (GenBank Accession No. MZ042367 and MZ042368) showed 99.66% - 99.92% identity to G. rostochiensis sequences available in GenBank (FJ212166.1, GQ294513, FJ212164.1 and KJ409617.1). Sequences from the 28S region (GenBank Accession No. MZ057597 and MZ057598) were 99.23% - 99.74% similar to those of G. rostochiensis isolate from Slovakia (KJ409625.1), Italy (KJ409631.1) and United Kingdom (KJ409633.1). We used species specific primers ITS5（5'-GGAAGTAAAAGTCGTAACAAGG-3'）and PITSr3 (5'AGCGCAGACATGCCGCAA-3') to amplify the product (Bulman & Marshall 1997; EPPO 2017). A single 434bp fragment was obtained from Hezhang and Weining populations. A host test for the Hezhang and Weining populations were performed by inoculating 1,000 eggs per plant of varieties Qingshu 9, Huize 2 and Hezuo 88 grown in the pots containing 800 cm3 of sterilized soil (soil: sand ratio was 3:1), and four replications were tested in greenhouse under 16 h light, 22°C in the day and 8 h dark in the night. At 90 days post inoculation, 32.6 ± 7, 31.2 ± 8, and 29.5 ± 8 females and cysts were extracted from the infected roots and soils of the varieties Qingshu 9, Huize 2 and Hezuo 88, respectively. No females and cysts were observed on the control plants. The trial indicated that potato cultivars Qingshu 9, Huize 2 and Hezuo 88 are hosts for the Hezhang and Weining populations of Globodera rostochiensis. To the best of our knowledge, this is the first detection of potato cyst nematode Globodera rostochiensis in Guizhou Province, China.

GLYCINE-RICH RNA-BINDING PROTEIN 7 potentiates effector-triggered immunity through an RNA recognition motif.

The activity of intracellular plant nucleotide-binding leucine-rich repeat (NB-LRR) immune receptors is fine-tuned by interactions between the receptors and their partners. Identifying NB-LRR interacting proteins is therefore crucial to advance our understanding of how these receptors function. A co-immunoprecipitation/mass spectrometry screening was performed in Nicotiana benthamiana to identify host proteins associated with the resistance protein Gpa2, a CC-NB-LRR immune receptor conferring resistance against the potato cyst nematode Globodera pallida. A combination of biochemical, cellular, and functional assays was used to assess the role of a candidate interactor in defense. A N. benthamiana homolog of the GLYCINE-RICH RNA-BINDING PROTEIN7 (NbGRP7) protein was prioritized as a Gpa2-interacting protein for further investigations. NbGRP7 also associates in planta with the homologous Rx1 receptor, which confers immunity to Potato Virus X. We show that NbGRP7 positively regulates extreme resistance by Rx1 and cell death by Gpa2. Mutating the NbGRP7 RNA recognition motif (RRM) compromises its role in Rx1-mediated defense. Strikingly, ectopic NbGRP7 expression is likely to impact the steady-state levels of Rx1, which relies on an intact RRM. Our findings illustrate that NbGRP7 is a pro-immune component in effector-triggered immunity by regulating Gpa2/Rx1 function at a posttranscriptional level.

PM 3/68 (2) Testing of potato varieties to assess resistance to Globodera rostochiensis and Globodera pallida

Specific scopeThis Standard describes the testing of potato varieties to assess resistance to the potato cyst nematodes Globodera rostochiensis and Globodera pallida. It should be used to fulfil requirements mentioned in PM 9/26 National regulatory control system for Globodera rostochiensis and Globodera pallida.Specific approval and amendmentFirst approved in 1990–091.Revised and edited as an EPPO Standard in 2006–09.First revision of the EPPO Standard approved in 2021–09. 2Authors and contributors are given in the Acknowledgements section.

Assessment of resistance of potato hybrids from the Russian Potato Research Center’s collection to Globodera rostochiensis

The potato cyst nematodes (PCN) Globodera rostochiensis and Globodera pallida are the most common pests feeding on potato roots. These pests have an aggressive distribution dynamic and bring a lot of damage to yield. The study presents results of comprehensively test new potato genotypes for resistance to the golden potato nematode (Globodera rostochiensis), for its further use in breeding and the creation of economically valuable resistant varieties. Almost half of the samples showed laboratory resistance to golden potato nematode, the rest were susceptible. 26 samples have shown the presence of two molecular markers (N146, N19), indicating the presence of H1 gene. Almost all samples showed a correspondence between laboratory resistance and the presence of H1 gene markers.

Monosaccharide Constituents of Potato Root Exudate Influence Hatching of the White Potato Cyst Nematode

Plants secrete a large array of compounds into the rhizosphere to facilitate interactions with their biotic environment. Some of these exuded compounds stimulate the hatching of obligate plant-parasitic nematodes, ultimately leading to a detrimental effect on the host plant. Determining these cues can help to provide new mechanisms for control and aid nematode management schemes. Here, we show that glucose, fructose, and arabinose, which are all present in potato root exudate (PRE), induce hatching of white potato cyst nematode (Globodera pallida) eggs whereas five other PRE sugars had no effect. Although these monosaccharides resulted in significant hatching, none induced the same level as PRE, suggesting that other components, possibly in combination, contribute to stimulation of nematode hatching. Glucose but not arabinose or fructose was also observed to attract juvenile G. pallida, indicating that these hatch-inducing components can have different roles in different stages of the life cycle. Applying a solution of these monosaccharides to G. pallida-infested soil prepotato planting initiated hatching in the absence of a host. Host absence resulted in nematode mortality and a reduction in the G. pallida population. Therefore, subsequent invasion of the crop postplanting was also reduced compared with untreated soil. Our data suggest that monosaccharide components of PRE play an important role in the hatching and attraction of G. pallida. As a result, the hatch-inducing monosaccharides can be applied as a preplanting treatment to induce hatching and reduce subsequent infection rates. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

The GpIA7 effector from the potato cyst nematode Globodera pallida targets potato EBP1 and interferes with the plant cell cycle programme.

The potato cyst nematode Globodera pallida acquires all of its nutrients from an elaborate feeding site that it establishes in a host plant root. Normal development of the root cells is re-programmed in a process coordinated by secreted nematode effector proteins. The biological function of the G. pallida GpIA7 effector was investigated in this study. GpIA7 is specifically expressed in the subventral pharyngeal glands of pre-parasitic stage nematodes. Ectopic expression of GpIA7 in potato plants affected plant growth and development, suggesting a potential role for this effector in feeding site establishment. Potato plants overexpressing GpIA7 were shorter, with reduced tuber weight and delayed flowering. We provide evidence that GpIA7 associates with the plant growth regulator StEBP1 (ErbB-3 epidermal growth factor receptor-binding protein 1). GpIA7 modulates the regulatory function of StEBP1, altering the expression level of downstream target genes, including ribonucleotide reductase 2, cyclin D3;1, and retinoblastoma related 1, which are down-regulated in plants overexpressing GpIA7. We provide an insight into the molecular mechanism used by the nematode to manipulate the host cell cycle and demonstrate that this may rely, at least in part, on hindering the function of host EBP1.

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

The potato cyst nematode (PCN) Globodera pallida has acquired significant importance throughout Europe due to its nefarious effects on potato production. Rapid and reliable diagnosis of PCN is critical during the surveillance programs and for the implementation of control measures. Molecular DNA-based methods are available, but they require expensive laboratory facilities, equipment and trained technicians. Moreover, there is an additional need of time for sample shipment and testing. In this work, we have developed a new and simple assay which reliably discriminates G. pallida from other cyst nematodes in less than 40 min. This assay may be applied either on cysts or juveniles with the ability to detect a single juvenile of G. pallida in a sample of at least 40 juveniles of the non-target species G. rostochiensis. This test should be a tool to improve the performance of the laboratory and has the potential to be performed on-site.

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

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.

The Genomic Impact of Selection for Virulence against Resistance in the Potato Cyst Nematode, Globodera pallida.

Although the use of natural resistance is the most effective management approach against the potato cyst nematode (PCN) Globodera pallida, the existence of pathotypes with different virulence characteristics constitutes a constraint towards this goal. Two resistance sources, GpaV (from Solanum vernei) and H3 from S. tuberosum ssp. andigena CPC2802 (from the Commonwealth Potato Collection) are widely used in potato breeding programmes in European potato industry. However, the use of resistant cultivars may drive strong selection towards virulence, which allows the increase in frequency of virulent alleles in the population and therefore, the emergence of highly virulent nematode lineages. This study aimed to identify Avirulence (Avr) genes in G. pallida populations selected for virulence on the above resistance sources, and the genomic impact of selection processes on the nematode. The selection drive in the populations was found to be specific to their genetic background. At the genomic level, 11 genes were found that represent candidate Avr genes. Most of the variant calls determining selection were associated with H3-selected populations, while many of them seem to be organised in genomic islands facilitating selection evolution. These phenotypic and genomic findings combined with histological studies performed revealed potential mechanisms underlying selection in G. pallida.

Identification and characterisation of serotonin signalling in the potato cyst nematode Globodera pallida reveals new targets for crop protection.

Plant parasitic nematodes are microscopic pathogens that invade plant roots and cause extensive damage to crops. We have used a chemical biology approach to define mechanisms underpinning their parasitic behaviour: We discovered that reserpine, a plant alkaloid that inhibits the vesicular monoamine transporter (VMAT), potently impairs the ability of the potato cyst nematode Globodera pallida to enter the host plant root. We show this is due to an inhibition of serotonergic signalling that is essential for activation of the stylet which is used to access the host root. Prompted by this we identified core molecular components of G. pallida serotonin signalling encompassing the target of reserpine, VMAT; the synthetic enzyme for serotonin, tryptophan hydroxylase; the G protein coupled receptor SER-7 and the serotonin-gated chloride channel MOD-1. We cloned each of these molecular components and confirmed their functional identity by complementation of the corresponding C. elegans mutant thus mapping out serotonergic signalling in G. pallida. Complementary approaches testing the effect of chemical inhibitors of each of these signalling elements on discrete sub-behaviours required for parasitism and root invasion reinforce the critical role of serotonin. Thus, targeting the serotonin signalling pathway presents a promising new route to control plant parasitic nematodes.

Monitoring and tackling genetic selection in the potato cyst nematode Globodera pallida

Management of plant pests is probably the most serious challenge in sustainable food production and the maintenance of food security. Due to the strict regulation of or ban on major categories of pesticide, the potato cyst nematode Globodera pallida has been managed by a combination of crop rotation and the potato resistance locus Grp1, a relatively narrow range resistance gene which was introgressed into a range of commercial potato cultivars in Europe. However, in 2014, G. pallida populations were described that can no longer be controlled by Grp1. Most likely similar highly virulent populations will also emerge in all major potato growing areas in North Western Europe where production practices are very similar. Except for laborious, costly and often moderately accurate pot experiments, there is currently no rapid and reliable method to identify virulent populations. This represents a strong limitation and prevents an accurate and durable management of infestations. The PalAdapt project funded by EFSA represents the first step of a European battle plan against the emergence of virulent G. pallida populations and aims at improving the methods and tools for a fast identification of virulence outbreaks. Four main research questions were investigated during the project: (i) Do resistance breaking populations correspond to novel introductions into Europe? (ii) Can miniaturized in vitro tests be used to get more rapidly an accurate identification of the virulence status?, (iii) Is cyst size a life history trait useful to estimate the virulence status of a population?, (iv) Can we identify polymorphism to design molecular tools for an accurate virulence monitoring? The EFSA partnering grants initiative was an accurate way to improve the EU risk assessment capacity through a knowledge exchange among partners having complementary resources and expertise.

ABOUT EFFECTS OF SOME NEUROPEPTIDES ON LOCOMOTOR BEHAVIOR OF CYST-FORMING PLANT NEMATODES

The article presents an analysis of world literature on the study of the physiological and functional significance of FMRFamide-like neuropeptides in the neurobiology of cyst-forming plant parasitic nematodes (by the example of larvae of the 2-yearold potato cyst nematode Globodera pallida and G. rostochiensis, and soybean cyst nematode Heterodera glycines). It was shown that the basic physiological and functional characteristics of FMRFamide-like neuropeptides were obtained from the effects that have some neuropeptides on the motor activity of intact nematode larvae, and molecular studies of flp-genes that encode FMRFamidelike neuropeptides. FMRFamide-like neuropeptides belong to the largest and most diverse family of signal neuropeptides found in invertebrate animals including numerous representatives of the Nematoda type which can significantly modulate the locomotor behavioral reactions of these animals. The work discusses a physiological function of FMRFamide-like neuropeptides and the identified putative receptor of one of the neuropeptides in locomotor behavioral reactions that ensure the vital activity of cyst-forming nematodes, and the possibility of using the data in developing new targeted anthelmintics. The fact of revealing the peptidergic nervous system in cyst-forming plant nematodes, parasitic nematodes of vertebrate animals and freeliving nematodes confirms the concept about the conservation of the peptidergic nervous system in representatives of the entire Nematoda type in general.

Plant-parasite coevolution: A weak signature of local adaptation between Peruvian Globodera pallida populations and wild potatoes.

Plant–parasite coevolution has generated much interest and studies to understand and manage diseases in agriculture. Such a reciprocal evolutionary process could lead to a pattern of local adaptation between plants and parasites. Based on the phylogeography of each partner, the present study tested the hypothesis of local adaptation between the potato cyst nematode Globodera pallida and wild potatoes in Peru. The measured fitness trait was the hatching of cysts which is induced by host root exudates. Using a cross‐hatching assay between 13 populations of G. pallida and root exudates from 12 wild potatoes, our results did not show a strong pattern of local adaptation of the parasite but the sympatric combinations induced better hatching of cysts than allopatric combinations, and there was a negative relationship between the hatching percentage and the geographical distance between nematode populations and wild potatoes. Moreover, a strong effect of the geographic origin of root exudates was found, with root exudates from south of Peru inducing better hatching than root exudates from north of Peru. These results could be useful to develop new biocontrol products or potato cultivars to limit damages caused by G. pallida.