Variation in resistance mechanisms to the green peach aphid among different Prunus persica commercial cultivars.
01 Oct 2012-Journal of Economic Entomology (Entomological Society of America)-Vol. 105, Iss: 5, pp 1844-1855
TL;DR: The peach cultivar ‘Elegant Lady’ and the nectarine ‘July Red-NS92’ exhibited a low occurrence of aphids in the orchard, a higher number of rejections in no-choice assays and no ingestion of phloem during the probing behavior experiments, suggesting prephloematic resistance.
Abstract: Peaches and nectarines are frequently attacked by the green peach aphid Myzus persicae (Sulzer), with significant negative impacts on fruit production. The genetic variability of resistance to this aphid among commercial cultivars of Prunus persica (L) Batsch and Prunus persica variety nectarina was evaluated in this study. In total, 16 cultivars of P. persica were selected to evaluate the occurrence and population growth rate of M. persicae in commercial orchards, as well as in no-choice and probing behavior laboratory assays. The results showed variability between cultivars in resistance and susceptibility to M. persicae, with three cultivars exhibiting different signatures of resistance. The peach cultivar ‘Elegant Lady’ exhibited a low occurrence of aphids in the orchard, a low rate of growth, moderate leaf-rejection in a no-choice test and a higher number and longer period of salivation into sieve elements, suggesting resistance at the phloematic level. The nectarine cultivar ‘August Red’ also exhibited low aphid occurrence in the orchard, a low rate of growth, and resistance at the prephloem and phloem levels. Finally, the nectarine ‘July Red-NS92’ exhibited a low occurrence of aphids in the orchard, a higher number of rejections in no-choice assays and no ingestion of phloem during the probing behavior experiments, suggesting prephloematic resistance. The rest of the cultivars studied exhibited clear susceptibility. Hence, different resistance mechanisms are apparent among the studied cultivars. The information gathered in this study regarding the resistance to M. persicae may assist breeding programs aimed at increasing aphid resistance to peaches and nectarines.
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TL;DR: The results suggest that under greenhouse conditions, pepper plant mutualism with AMF can increase pepper yield by reducing the numbers of the key pest, peach-potato aphid.
Abstract: In the present study sweet pepper plants, Capsicum annuum, were planted in greenhouse and open field conditions to test the effect of the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis on phytophagous and predatory arthropod populations. Furthermore, we tested the hypothesis that AMF may increase the crop yield (number of fruits and their weight) and activity level of polyphenol oxidase (PPO) and peroxidase (POD), enzymes that seemingly decrease infestation by arthropod pests. The most abundant arthropod species found were the peach-potato aphid, Myzus persicae, western flower thrips, Frankliniella occidentalis, and the seven-spot ladybird, Coccinella septempunctata. Sweet pepper mutualism with AMF significantly reduced colonization by the peach-potato aphid under greenhouse conditions. Aphid density increased, however, on two of four pepper varieties tested under open field conditions. The density of ladybird predators did not appear directly influenced by AMF under greenhouse conditions, whereas a significantly higher predator density was found on three out of four pepper plant varieties with fungal mutualism tested under field conditions. Crop yield was significantly higher on plants with AMF mutualism under greenhouse conditions, but no clear effects were detected under field conditions. Both PPO and POD activity increased significantly and remained higher than controls until day 14 of the experiment under mutualism with AMF, although only in the greenhouse. The results suggest that under greenhouse conditions, pepper plant mutualism with AMF can increase pepper yield by reducing the numbers of the key pest, peach-potato aphid.
16 citations
Cites background from "Variation in resistance mechanisms ..."
...Other economic impacts result from pathogenic virus transmission (Verdugo et al. 2012)....
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01 Jan 2013
TL;DR: Both short-term and long-term virulence loss were observed for virulent aphid populations differing in virulence level, which indicates this virulence is associated with fitness costs.
Abstract: Aphids are serious pests of crop plant species, and host plant resistance is often the most effective and environmentally friendly control strategy to control these pests. One of these aphid pests is the black currant - lettuce aphid, Nasonovia ribisnigri (Mosely), an economically important pest of cultivated lettuce, Lactuca sativa L. Host plant resistance has been used since 1982 to control this aphid species and is mediated by the Nr-gene, originating from wild lettuce Lactuca virosa L. However, this resistance is not effective anymore, since N. ribisnigri aphids virulent to the Nr-resistance have been reported since 2007. The aim of this thesis was to unravel the mechanism of resistance mediated by the Nr-gene against N. ribisnigri, by behavioural studies on the aphids on both resistant and susceptible lettuce, to allow lettuce breeders to accelerate their resistance breeding programmes. Although the exact mechanism of Nr-mediated resistance remains unknown, the data in this thesis provide insight into this mechanism. The active site of the Nr-mediated resistance is mainly located in the phloem and some resistance might be encountered by the aphids along the pathway to the phloem. The inability of the avirulent aphids to feed from the resistant plant could be caused by the failure of aphids to suppress the wound response of the sieve element. The resistance factor(s) are only produced in the shoot, because grafts with resistant shoots and susceptible roots were resistant, whereas grafts with susceptible shoots and resistant roots remained susceptible. An intact vascular system is needed for full resistance, because both detached leaves and leaf disks of resistant lettuce plants were less resistant. Variation in virulence was observed among populations of different geographical origin. Aphids from a highly virulent population performed equally well on both resistant and susceptible lettuce plants, whereas semi-virulent aphids performed better on susceptible lettuce plants. Both short-term and long-term virulence loss were observed for virulent aphid populations differing in virulence level, which indicates this virulence is associated with fitness costs. A possible mechanism underlying virulence in N. ribisnigri to the Nr-resistance is the presence of an effector protein in the salivary secretion of the aphids suppressing resistance. Virulent aphids seemed to actively suppress the resistance in lettuce against the avirulent aphids. The original donor or the Nr-resistance, L. virosa accession IVT 280, was tested as possible source of new resistance against the virulent biotypes of N. ribisnigri and was foundfully resistant against virulent aphids, and can be exploited as a source of resistance in breeding for new resistance in cultivated lettuce.
10 citations
TL;DR: La revue bibliographique suggere egalement un role des pratiques culturales dans les interactions pecher-puceron, tandis que le developpement of modeles predictifs visant a assister les systemes de gestion des bio-agresseurs necessite the collecte of davantage de donnees.
Abstract: La complexite des interactions insectes-plantes en fonction de differents niveaux de ressources et de resistance de l’hote : le cas de Myzus persicae-Prunus persica (synthese bibliographique) Introduction. Les interactions plantes-insectes sont influencees directement ou indirectement par plusieurs facteurs de stress. Dans cette synthese bibliographique, l’effet de la disponibilite des ressources sur ces interactions est en premier lieu aborde au sens large, suivi d’une analyse ciblee des relations impliquant le modele puceron, en particulier le puceron vert du pecher Myzus persicae et son hote principal, Prunus persica. Litterature. Les defenses des plantes envers les insectes se manifestent de deux facons : la resistance et la tolerance, toutes deux influencees par des facteurs abiotiques. Les informations recueillies a partir d’etudes (n = 29) concernant l'effet de la diminution de la disponibilite en eau sur les defenses contre les insectes, ont montre que dans 41,4 % des etudes, le stress hydrique induit la resistance. Dans 34,5 %, 20,1 % et 3,4 %, les effets sur la resistance etaient respectivement moindres, absents et conditionnels. Conclusions. Le stress hydrique provoque des effets mitiges sur la resistance des plantes aux pucerons. Toutefois, la revue bibliographique suggere egalement un role des pratiques culturales dans les interactions pecher-puceron, tandis que le developpement de modeles predictifs visant a assister les systemes de gestion des bio-agresseurs necessite la collecte de davantage de donnees.
8 citations
TL;DR: 1.1.
Abstract: 1 Selection does not only operate in a genotype (G) × environment (E) context, but can also be modulated by the activities of organisms interacting with their environment (G × G × E)
2 The influences of aphid clonal identity and host plant (Vicia faba) intraspecific genetic variation on the performance of five genotypes of pea aphid (Acyrthosiphon pisum) were investigated – with and without interaction with a competing heterospecific clone of vetch aphid (Megoura viciae) – across three cultivars of V faba
3 Pea aphid performance in the presence of a competing vetch aphid clone (G × G × E) compared with the absence of competition (G × E) revealed strong context-dependent, genotype-specific shifts in performance, influenced by plant cultivar, competitor presence and their interaction
4 The performance of vetch aphid in competition with each pea aphid clone was also compared Here, competitor's genotype and abundance underlay a remarkably varied response by vetch aphid across interactions
5 The study shows that aphid genotypes exhibit a varying degree of risk spreading, contingent on competitor identity and the patterns of aggregation across three plant cultivars Owing to feedback loops between species activities and selective forces acting on them, our findings suggest that there are context-dependent responses by competitors that are shaped via the interplay of the co-occurring species and their biotic environment
6 This work highlights the complexity of species interactions and the importance of investigating reciprocity between competition and intraspecific genetic variation A better understanding of the eco-evolutionary interactions between phloem-feeding insects and their host plants can potentially be used to enhance crop protection and pest control
3 citations
Cites background from "Variation in resistance mechanisms ..."
...Driven by the necessity to multiply, thrive, and offset plant countermeasures (Dawkins, 1989; Walling, 2008; Verdugo et al., 2012), the aphid genotypes in our study responded differentially to competition by modifying their reproductive rates and aggregation behaviour to counteract the adversity of competition (Dawkins, 1982)....
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...On different cultivars with varying resistance to pest infestation (Dogimont et al., 2010; Verdugo et al., 2012), co-existing aphid species are expected to vary their reproductive and behavioural means to cope with the constantly changing environment (Dixon, 1998; Whitman & Agrawal, 2009;…...
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...Driven by the necessity to multiply, thrive, and offset plant countermeasures (Dawkins, 1989; Walling, 2008; Verdugo et al., 2012), the aphid genotypes in our study responded differentially to competition by modifying their reproductive rates and aggregation behaviour to counteract the adversity of…...
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...…quality of their hosts (Sandström, 1994); (ii) variation in plant resistance (Fritz & Simms, 1992; Kaloshian & Walling, 2005; Dogimont et al., 2010; Verdugo et al., 2012) and aphid countermeasures (Walling, 2008); and (iii) inter-player identity within the G×G×E context (Strauss et al., 2004;…...
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...These relatively positive or negative effects of interspecific competition on pea aphid fitness can be attributed to a group of diffusely acting factors, including: (i) a differential response of aphid genotype to the differences in dietary quality of their hosts (Sandström, 1994); (ii) variation in plant resistance (Fritz & Simms, 1992; Kaloshian & Walling, 2005; Dogimont et al., 2010; Verdugo et al., 2012) and aphid countermeasures (Walling, 2008); and (iii) inter-player identity within the G×G×E context (Strauss et al....
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Dissertation•
01 Dec 2016
TL;DR: The combination of EPG and transcriptomics provides an opportunity to assess brassica germplasm for further research into defence mechanisms of cabbage aphids and identified strong candidate genes for aphid resistance.
Abstract: Brassica crops are grown worldwide for food, oil, medicinal and crop rotation properties. They suffer from insect pests which cause large yield and economic losses. Application of insecticides is the preferred way of dealing with insect problems, but it is not only hazardous to the environment, it also affects humans as the chemicals easily get incorporated into the food chain. As a result, new more resistant varieties are urgently needed to meet the demand of growing populations.
A set of 200 accessions were classified as resistant (non-preferred) or susceptible (preferred) in response to cabbage aphid feeding in the field. Fifteen accessions were further assessed to characterize and identify the level and location of resistance factors by investigating feeding behaviour of cabbage aphid using the Electrical Penetration Graph (EPG) technique. The feeding behaviour assessment revealed the presence of interspecific & intraspecific variation and presence of resistance factors at multiple levels.
The transcriptional response of these accessions under presence and absence of aphid feeding for 24h showed that gene expression is highly regulated in response to aphid feeding. Gene ontology (GO) enrichment study helped identify strong candidate genes for aphid resistance. In addition to this, the gene expression differences between CWR and landraces indicated adaptations of landraces during the process of domestication. Lastly, Gene expression data was used to develop models to predict insect resistance status.
In conclusion, the combination of EPG and transcriptomics provides an opportunity to assess brassica germplasm for further research into defence mechanisms of cabbage aphids.
2 citations
Cites background or methods from "Variation in resistance mechanisms ..."
...Interspecies as well as intra-species variation in level of resistance against aphid feeding in Brassica species are reported in the literature (Verdugo et al. 2012; Cole 1994; Broekgaarden et al. 2007)....
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...)Batsch) and nectarine (Prunus persica variety nectarina) has been evaluated using feeding behaviour assessment by EPG (Verdugo et al. 2012)....
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...EPG studies have produced reliable information concerning the location of the resistance mechanisms (Verdugo et al. 2012)....
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References
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Book•
01 Jan 1997TL;DR: This comprehensive evaluation and synthesis of a rapidly-developing field provides state-of-the-discipline reviews, and highlights areas of research which might be productive, should appeal to a wide variety of theoretical and applied researchers.
Abstract: Plants face a daunting array of creatures which eat them, bore into them and use virtually every plant part for food or shelter. However, plants are far from defenceless under attack. Although they cannot flee their attackers, they can produce defences, such as thorns, and can actively alter their chemistry and physiology in response to damage. For instance, young potato leaves being eaten by potato beetles respond by producing chemicals which inhibit beetle digestive enzymes. Research on these induced responses to herbivory has proceeded since the 1980s, and this comprehensive evaluation and synthesis of a rapidly-developing field provides state-of-the-discipline reviews, and highlights areas of research which might be productive. This overview should appeal to a wide variety of theoretical and applied researchers in ecology, evolutionary biology, plant biology, entomology and agriculture.
2,385 citations
"Variation in resistance mechanisms ..." refers background in this paper
...…a positive PGR in this cultivar, suggesting that despite an initial antixenotic effect, aphids are likely able to develop induced susceptibility under such experimental conditions, as shown in other aphid-plant systems (Karban and Baldwin 1997, Prado and Tjallingii 1997, Gonzales et al. 2002)....
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Book•
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01 Jun 1995
TL;DR: This book explains in detail the basic concepts of exponential and logistic population growth, age-structured demography, metapopulation dynamics, competition, predation and island biogeography.
Abstract: Prefaces - Exponential Population Growth - Logistic Population Growth - Age-Structured Population Growth - Metapopulation Dynamics - Competition - Predation - Island Biogeography - Succession - Problems - Appendix: Working with Differential Equations - Solutions to Problems - Glossary - Literature Cited - Index
698 citations
TL;DR: Two completely serially sectioned probes from the epidermis to the phloem were reconstructed and severed stylets in the plant tissue were processed for transmission electron microscopy (TEM) and sectioned either transverse or longitudinal to the stylets.
Abstract: . Plant penetration by Aphis fabae (Scopoli) was recorded by the electrical penetration graph (EPG) technique and followed by stylectomy during wave-forms that were suspected of indicating sieve element punctures. The severed stylets in the plant tissue were subsequently processed for transmission electron microscopy (TEM) and sectioned either transverse or longitudinal to the stylets. Two completely serially sectioned probes from the epidermis to the phloem were reconstructed.
In one probe the stylet pathway went to a sieve element and showed many empty branches of salivary sheath material. Breaks in cell walls filled with sheath material demonstrated that the majority of cells bordering the track had been punctured, which supports earlier evidence from EPGs. All types of cells showed punctures and the highest number was found inside the vascular bundle. Very few cells died, which would appear to be important for virus transmission, and in others cellular reactions remained limited to some callose formation. The route of the stylets was intercellular and passed through the secondary wall material. The role of pectinase in intercellular penetration, and previous evidence for intracellular tracks are discussed. Most sieve elements had been punctured but only one was eventually accepted. Thus, reaching a sieve element in a host plant does not automatically imply its acceptance though the reason remains unclear. Gelation of phloem proteins was shown in the stylet canal.
In a second probe, plant cytological and morphological correlations with the EPG were emphasized. Probes by other aphid-plant combinations showed great similarity.
567 citations
"Variation in resistance mechanisms ..." refers background in this paper
...Different types of signals are emitted depending on the location and activities performed by the aphid stylet inside the plant tissue (Tjallingii and Esch 1993, Alvarez et al. 2006)....
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TL;DR: It is suggested that the dominant cues controlling plant preference and initiation of reproduction are detected early during the stylet penetration process, well before the nutrient supply (phloem) is contacted.
Abstract: ▪ Abstract As phloem feeders and major vectors of plant viruses, aphids are important pests of agricultural and horticultural crops worldwide. The processes of aphid settling and reproduction on plants therefore have a direct economic impact, and a better understanding of these events may lead to improved management strategies. Aphids are also important model organisms in the analysis of population differentiation and speciation in animals, and new ideas on plant utilization influence our understanding of the mechanisms generating biological diversity. Recent research suggests that the dominant cues controlling plant preference and initiation of reproduction are detected early during the stylet penetration process, well before the nutrient supply (phloem) is contacted. Aphids regularly puncture cells along the stylet pathway and ingest cytosolic samples, and the cues stimulating settling and parturition likely are metabolites present in peripheral (nonvascular) plant cells. We discuss these findings and t...
544 citations
"Variation in resistance mechanisms ..." refers background in this paper
...A short pds may be associated with the presence of intracellular metabolites that induce the rapid withdrawal of stylets (Powell et al. 2006)....
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TL;DR: This hypothesis that in order to prevent protein clogging inside a sieve element, ejection of watery saliva plays an important role is demonstrated by new experimental results and is related to new EPG results from plants with phloem-located resistance.
Abstract: Successful phloem feeding requires overcoming a number of phloem-related plant properties and reactions. The most important hurdle is formed by the phloem wound responses, such as coagulating proteins in the phloem sieve elements of the plant and in the capillary food canal in the insect's mouth parts, i.e. the stylets. It seems that in order to prevent protein clogging inside a sieve element, ejection of watery saliva plays an important role. This ejection is detected in the electrical penetration graph (EPG) as E1 salivation and always precedes phloem sap ingestion. During this feeding from sieve elements, another regular and concurrent salivation also occurs, the watery E2 salivation. This E2 saliva is added to the ingested sap and, it probably prevents phloem proteins from clogging inside the capillary food canal. Whatever the biochemical mode of action of the inhibition of protein coagulation might be, in some plants aphids do not seem to be able to prevent clogging, which may explain the resistance to aphids in these plants. The relevance of this hypothesis is demonstrated by new experimental results and is related to new EPG results from plants with phloem-located resistance.
469 citations
"Variation in resistance mechanisms ..." refers background in this paper
...These drops can be divided into subphases I, II-1, II-2, II-3, and III (Powell 2005, Tjallingii 2006, Tjallingii et al. 2010)....
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...It is particularly interesting to note that in this cultivar, salivation after sieve element puncture (E1) correlated negatively with PGR, which has been found to occur more frequently in aphidresistant plants (Klingler et al. 1998, Ramṍrez and Niemeyer 1999, Tjallingii 2006)....
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