scholarly journals UPLC-MS/MS analysis and biological activity of the potato cyst nematode hatching stimulant, solanoeclepin A, in the root exudate of Solanum spp.

Planta ◽  
2021 ◽  
Vol 254 (6) ◽  
Author(s):  
Alessandra Guerrieri ◽  
Kristýna Floková ◽  
Lieke E. Vlaar ◽  
Mario L. Schilder ◽  
Gertjan Kramer ◽  
...  

Abstract Main conclusion Solanoeclepin A is a hatching stimulant for potato cyst nematode in very low (pM) concentrations. We report a highly sensitive method for the analysis of SolA in plant root exudates using UHPLC-MS/MS and show that there is considerable natural variation in SolA production in Solanum spp. corresponding with their hatching inducing activity. Abstract Potato cyst nematode (PCN) is a plant root sedentary endoparasite, specialized in the infection of solanaceous species such as potato (Solanum tuberosum) and tomato (Solanum lycopersicum). Earlier reports (Mulder et al. in Hatching agent for the potato cyst nematode, Patent application No. PCT/NL92/00126, 1996; Schenk et al. in Croat Chem Acta 72:593–606, 1999) showed that solanoeclepin A (SolA), a triterpenoid metabolite that was isolated from the root exudate of potato, induces the hatching of PCN. Its low concentration in potato root exudate has hindered progress in fully understanding its hatching inducing activity and exploitation in the control of PCN. To further investigate the role of SolA in hatching of PCN, the establishment of a highly sensitive analytical method is a prerequisite. Here we present the efficient single-step extraction and UHPLC-MS/MS based analysis for rapid determination of SolA in sub-nanomolar concentrations in tomato root exudate. This method was used to analyze SolA production in different tomato cultivars and related solanaceous species, including the trap crop Solanum sisymbriifolium. Hatching assays with PCN, Globodera pallida, with root exudates of tomato genotypes revealed a significant positive correlation between SolA concentration and hatching activity. Our results demonstrate that there is natural variation in SolA production within solanaceous species and that this has an effect on PCN hatching. The analytical method we have developed can potentially be used to support breeding for crop genotypes that induce less hatching and may therefore display reduced infection by PCN.

2018 ◽  
Author(s):  
Anna Crisford ◽  
Fernando Calahorro ◽  
Elizabeth Ludlow ◽  
Jessica M.C. Marvin ◽  
Jennifer K. Hibbard ◽  
...  

AbstractPlant parasitic nematodes are microscopic pests that invade plant roots and cause extensive damage to crops worldwide. To investigate mechanisms underpinning their parasitic behaviour we used a chemical biology approach: We discovered that reserpine, a plant alkaloid known for its antagonism of the mammalian vesicular monoamine transporter VMAT and ability to impart a global depletion of synaptic biogenic amines in the nervous system, potently impairs the ability of the potato cyst nematode Globodera pallida to enter the host plant root. We show that this effect of reserpine is mediated by an inhibition of serotonergic signalling that is essential for activation of the stylet, a lance-like organ that protrudes from the mouth of the worm and which is used to pierce the host root to gain access. 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 found that inhibitors of tryptophan hydroxylase, SER-7 and MOD-1 phenocopy the plant protecting action of reserpine. Thus targeting the serotonin signalling pathway presents a promising new route to control plant parasitic nematodes.SummaryIndian snakeroot, an herbal medicine prepared from the roots of the shrub Rauwolfia serpentina, has been used for centuries for its calming action. The major active constituent is reserpine which works by depleting a specific class of mood regulating chemical in the brain, the biogenic amines. We have discovered a remarkable effect of reserpine on a pest of global concern, the plant parasitic nematodes. These microscopic worms invade the roots of crops presenting a severe threat to food production. We show that reserpine disables serotonin signalling in the worm’s ‘brain’ that regulates the rhythmic thrusting of the stylet: a lance-like structure that protrudes from its mouth to pierce the plant root and which is essential to its parasitic lifecycle. Thus, reserpine joins nicotine as another intriguing example of Nature evolving its own protection against pests. We have identified key components of the serotonin signalling pathway in the potato cyst nematode Globodera pallida and show that chemicals that target these sites inhibit the ability of the nematode to invade its host plant. We conclude that biogenic amine transmitters are intimately involved in the worm’s parasitic behaviour and provide a new discrete route to crop protection.


Author(s):  
Christopher A Bell ◽  
Waddah Mobayed ◽  
Catherine J Lilley ◽  
Peter Urwin

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 pre-potato 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 post-planting was also reduced, compared to 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 pre-planting treatment to induce hatching and reduce subsequent infection rates.  


2021 ◽  
Vol 11 ◽  
Author(s):  
Bruno Ngala ◽  
Nicolas Mariette ◽  
Mélina Ianszen ◽  
Pauline Dewaegeneire ◽  
Marie-Christine Denis ◽  
...  

Cyst nematodes account for substantial annual yield losses in crop production worldwide. Concerns over environmental and health issues due to the use of chemical nematicides mean alternative sustainable and integrated solutions are urgently required. Hatch induction of encysted eggs in the absence of host plants, i.e., ‘suicide-hatching,’ could be a sustainable alternative in reducing population densities of cyst nematodes in infested soils. Here we examined in situ hatching of encysted eggs of Globodera pallida, Heterodera carotae, and Heterodera schachtii at varying soil depths, following exogenous applications of host root exudates in repeated glasshouse experiments. Cysts were retrieved 30 or 43 days post-incubation depending on the nematode species and assessed for hatching rates relative to the initial number of viable eggs per cyst. Hatching of the potato cyst nematode G. pallida depended on both soil moisture and effective exposure to root exudates, and to a lesser extent on exudate concentration. The carrot cyst nematode H. carotae had over 75% hatched induced by root exudate irrespective of the concentration, with better hatch induction at 20 cm as compared with 10 cm soil depth. Hatching of the beet cyst nematode H. schachtii largely depended on the soil moisture level at constant temperature, rather than the type or concentration of root exudates applied. As a conclusion, exogenously applied host root exudates may play a major role in inducing in situ hatch of encysted eggs of potato and carrot cyst nematodes in the absence of host plant under favorable soil temperature/moisture conditions. To improve such strategy, the characterization of chemical profiles of the root exudate composition and field validation are currently ongoing.


1982 ◽  
Vol 99 (2) ◽  
pp. 325-328 ◽  
Author(s):  
M. F. B. Dale ◽  
M. S. Phillips

SUMMARYThe inheritance of resistance to Globodera pallida was studied in seedling progenies derived from Solanum tuberosum ssp. andigena CPC 2802 (H3) and S. vernei and compared with resistance to G. rostochiensis derived from S. tuberosum ssp. andigena CPC 1673(H1). The resistance of CPC 2802 was originally thought to be due to a major gene (H3), but results presented here demonstrate that it and that derived from S. vernei are inherited in a similar manner quite distinct from the major gene inheritance from CPC 1673 (HI). It is concluded that the resistances derived from CPC 2802 and S. vernei are both polygenic in nature. These findings are discussed in relation to breeding policy and screening methods.


Nematology ◽  
2004 ◽  
Vol 6 (3) ◽  
pp. 375-387 ◽  
Author(s):  
N. Aileen Ryan ◽  
Peter Jones

AbstractSeventy bacteria, isolated from the rhizosphere of the potato cyst nematode (PCN) host plant, potato, were cultured in the presence and absence of potato root leachate (PRL) and the resultant culture filtrates were analysed for their ability to affect the hatch in vitro of the two PCN species. Of the isolates tested, nine had a significant effect on PCN hatch. Six affected Globodera pallida hatch and three affected G. rostochiensis hatch. Five of the isolates significantly increased hatch only when cultured in the presence of PRL. Three of the isolates decreased PCN hatch significantly in PRL. Only one isolate increased hatch significantly in the absence of PRL. No isolate affected the hatch of both species. Six of the nine isolates that significantly affected PCN hatch had been pre-selected by culturing on PRL. Bacterial isolates from PCN non-hosts (14 from wheat, 17 from sugar beet) were also tested for hatching activity. The principal effect of the hatch-active isolates from the PCN non-host plants was to increase PCN hatch in the presence of PRL. In contrast to the host bacteria results, the isolates from non-host plants affected only G. rostochiensis hatch (three wheat isolates and four sugar beet isolates significantly increased G. rostochiensis hatch); no such isolate affected G. pallida hatch significantly in the presence of PRL. Ten isolates (32%) from non-host plants had the ability to increase significantly the hatch of PCN in the absence of PRL (eight of these affected G. rostochiensis hatch and four affected G. pallida hatch), compared to only one bacterial isolate (1%) from a host plant. The majority of the isolates from non-hosts produced PCN species-specific effects, as with the bacteria isolated from potatoes, although two wheat isolates increased the hatch of both species significantly in the absence of PRL. Of 20 hatch-active bacterial isolates (from all three plants) identified, 70% were Bacillus spp. Other genera identified were Arthrobacter , Acinetobacter and Staphylococcus .


Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1429
Author(s):  
Kyriakos Varypatakis ◽  
Pierre-Yves Véronneau ◽  
Peter Thorpe ◽  
Peter J. A. Cock ◽  
Joanne Tze-Yin Lim ◽  
...  

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.


Nematologica ◽  
1998 ◽  
Vol 44 (6) ◽  
pp. 655-666 ◽  
Author(s):  
B.E. Harrower ◽  
A. Ploeg ◽  
V.C. Blok ◽  
M.S. Phillips

Parasitology ◽  
1991 ◽  
Vol 103 (1) ◽  
pp. 149-155 ◽  
Author(s):  
F. Grundler ◽  
L. Schnibbe ◽  
U. Wyss

The behaviour of Heterodera schachtii second-stage juveniles in response to mustard (Sinapis alba) rooxudates was observed and analysed under aseptic conditions in a standardized bioassay. Aggregation of juveniles on an agarose layer occurred within less than 30 min in the area where root exudates had been applied and persisted for several hours. Analysis of time-lapse video recordings showed that the aggregation did not result from a directed orientation of the juvenile towards the root exudate. This was supported by an orientation assay using single juveniles. Aggregated juveniles showed pre-infection exploratory behaviour, including stylet thrusting and head-end bending, while staying at rest for several minutes.


Plant Disease ◽  
2014 ◽  
Vol 98 (4) ◽  
pp. 575-575 ◽  
Author(s):  
B. Nježić ◽  
B. Gerič Stare ◽  
S. Širca ◽  
N. Grujić

Potato cyst nematodes (PCN), the golden cyst nematode Globodera rostochiensis (Woll.) Bahrens, and the pale potato cyst nematode G. pallida (Stone) stand out by their remarkable and efficient parasitic adaptations causing high economic losses in potato production worldwide. They are A2 quarantine pests in EPPO countries as well as in Bosnia and Herzegovina. Up to now, only G. rostochiensis was reported from Bosnia and Herzegovina in 2011 (1). A systematic survey on the presence of PCN on entire territory of Bosnia and Herzegovina started in 2011. During the PCN survey, each year 120 soil samples of 1.5 liters were collected in the Republic of Srpska, one of the two entities of Bosnia and Herzegovina. The samples were collected by soil auger 10 cm in length with a diameter of 1.5 cm consisting of 100 cores. Entire samples were processed by Seinhorst elutriator (4). In autumn of 2012, PCN viable cysts were found in two soil samples originating from one field. From one sample, 12 cysts were extracted, and 2 from another sample. The morphology of cysts and second stage juveniles and molecular analysis established the identity of this species as pale cyst nematode G. pallida (3). In addition, the sequencing of the ribosomal DNA region revealed unequivocal similarity to G. pallida (GenBank Accession No. HF968449), while PCR-RFLP analysis (2) showed European type of G. pallida. The infested field is located in Rogatica, 70 km east of Sarajevo, which is one of the main seed and potato production areas in Bosnia and Herzegovina. The field history revealed that farm-propagated, farm-saved seed potatoes could spread the nematodes to other fields as well. Therefore, 26 additional samples were taken from the fields that belong to the infested field owner and the surrounding fields, but no cysts were found in additional samples. To determine infestation focus and its size, the infested field (1.1 ha) was divided into 46 plots (25 × 10 m) and resampled by taking samples of 60 cores per plot. The detailed sampling of the field revealed a high infestation of 1 cyst per gram of soil in the infestation focus. The high infestation level and the propagation of farm-own seed potatoes suggest that the introduction of G. pallida might have occurred several years ago, probably with imported seed potatoes. The infested field was subjected to the phytosanitary measure of banning potato production for a period of 6 years with the possibility of its prolongation, if cysts with live content are found afterward. It is expected that the nematode is present in other fields due to the farmer's practices of propagating farm-saved seed potatoes and deficient field machinery hygiene. Therefore, the whole area will be intensively monitored for the presence of PCN in the future. An adequate pest management plan will be prepared after PCN pathotype identification. To our knowledge, only one field was found infested with G. pallida during the 3-year PCN survey in Bosnia and Herzegovina. Strict phytosanitary measures for preventing further PCN introductions and spreading should be intensified. References: (1) I. Ostojić et al. Plant Dis. 95:883, 2011. (2) S. Širca et al. Phytopathol. Mediterr. 49:361, 2010. (3) A. M. Skantar et al. J. Nematol. 39:133, 2007. (4) J. van Bezooijen. Methods and Techniques for Nematology, Wageningen University, 2006.


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