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1.
Sci Rep ; 11(1): 23368, 2021 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-34862453

RESUMO

Insect pollination is among the most essential ecosystem services for humanity. Globally, bees are the most effective pollinators, and tropical bees are also important for maintaining tropical biodiversity. Despite their invaluable pollination service, basic distributional patterns of tropical bees along elevation gradients are globally scarce. Here, we surveyed bees at 100 m elevation intervals from 800 to 1100 m elevation in Costa Rica to test if bee abundance, community composition and crop visitor assemblages differed by elevation. We found that 18 of 24 bee species spanning three tribes that represented the most abundantly collected bee species showed abundance differences by elevation, even within this narrow elevational gradient. Bee assemblages at the two crop species tested, avocado and squash, showed community dissimilarity between high and low elevations, and elevation was a significant factor in explaining bee community composition along the gradient. Stingless bees (Tribe Meliponini) were important visitors to both crop species, but there was a more diverse assemblage of bees visiting avocado compared to squash. Our findings suggest that successful conservation of tropical montane bee communities and pollination services will require knowledge of which elevations support the highest numbers of each species, rather than species full altitudinal ranges.


Assuntos
Abelhas/classificação , Cucurbita/parasitologia , Persea/parasitologia , Altitude , Animais , Abelhas/fisiologia , Costa Rica , Filogenia , Polinização , Vigilância da População , Clima Tropical
2.
Molecules ; 26(21)2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34770754

RESUMO

Melon fly (Bactrocera cucurbitae) is the most common pest of cucurbits, and it directly causes damage to cucurbit fruits in the early developmental stage. The infection of fruit tissues induces oxidative damage through increased generation of cellular reactive oxygen species. The effects of melon fly infestation on the production of defensive enzymes and antioxidant capabilities in five cucurbit species, namely, bottle gourd, chayote, cucumber, snake gourd, and bitter gourd, were investigated in this study. The total phenolic and flavonoid content was considerably higher in melon fly infestation tissues compared to healthy and apparently healthy tissues. The chayote and bottle gourd tissues expressed almost 1.5- to 2-fold higher phenolic and flavonoid contents compared to the tissues of bitter gourd, snake gourd, and cucumber upon infestation. Defensive enzymes, such as peroxidase (POD), superoxide dismutase (SOD), polyphenol oxidase (PPO), and catalase (CAT), were high in healthy and infected tissues of chayote and bottle gourd compared to bitter gourd, snake gourd, and cucumber. The activity of POD (60-80%), SOD (30-35%), PPO (70-75%), and CAT (40-50%) were high in infected chayote and bottle gourd tissue, representing resistance against infestation, while bitter gourd, snake gourd, and cucumber exhibited comparatively lower activity suggesting susceptibility to melon fly infection. The antioxidant properties were also high in the resistant cucurbits compared to the susceptible cucurbits. The current research has enlightened the importance of redox-regulatory pathways involving ROS neutralization through infection-induced antioxidative enzymes in host cucurbit resistance. The melon fly infestation depicts the possible induction of pathways that upregulate the production of defensive enzymes and antioxidants as a defensive strategy against melon fly infestation in resistant cucurbits.


Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Cucurbita/química , Cucurbita/enzimologia , Tephritidae/efeitos dos fármacos , Animais , Cucurbita/genética , Cucurbita/parasitologia , Resistência à Doença , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Parasita , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Espécies Reativas de Oxigênio/metabolismo
3.
Phytopathology ; 110(2): 447-455, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31454304

RESUMO

Phytophthora capsici is a destructive pathogen of cucurbits that causes root, crown, and fruit rot. Winter squash (Cucurbita spp.) production is limited by this pathogen in Michigan and other U.S. growing regions. Age-related resistance (ARR) to P. capsici occurs in C. moschata fruit but is negated by wounding. This study aimed to determine whether structural barriers to infection exist in the intact exocarp of maturing fruit exhibiting ARR. Five C. moschata cultivars were evaluated for resistance to P. capsici 10, 14, 16, 18, and 21 days postpollination (dpp). Scanning electron microscopy imaging of Chieftain butternut fruit exocarp of susceptible fruit at 7 dpp and resistant fruit at 14 and 21 dpp revealed significant increases in cuticle and epidermal thicknesses as fruit aged. P. capsici hyphae penetrated susceptible fruit at 7 dpp directly from the surface or through wounds before 6 h postinoculation (hpi) and completely degraded the fruit cell wall within 48 hpi. Resistant fruit remained unaffected at 14 and 21 dpp. The high correlation between the formation of a thickened cuticle and epidermis in maturing winter squash fruit and resistance to P. capsici indicates the presence of a structural barrier to P. capsici as the fruit matures.


Assuntos
Cucurbita , Resistência à Doença , Frutas , Phytophthora , Cucurbita/parasitologia , Resistência à Doença/fisiologia , Frutas/citologia , Frutas/parasitologia , Phytophthora/fisiologia , Doenças das Plantas/parasitologia
4.
Sci Rep ; 9(1): 11870, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31413274

RESUMO

Using the hoary squash bee (Peponapis pruinosa) as a model, we provide the first probabilistic risk assessment of exposure to systemic insecticides in soil for ground-nesting bees. To assess risk in acute and chronic exposure scenarios in Cucurbita and field crops, concentrations of clothianidin, thiamethoxam and imidacloprid (neonicotinoids) and chlorantraniliprole (anthranilic diamide) in cropped soil were plotted to produce an environmental exposure distribution for each insecticide. The probability of exceedance of several exposure endpoints (LC50s) was compared to an acceptable risk threshold (5%). In Cucurbita crops, under acute exposure, risk to hoary squash bees was below 5% for honey bee LC50s for all residues evaluated but exceeded 5% for clothianidin and imidacloprid using a solitary bee LC50. For Cucurbita crops in the chronic exposure scenario, exposure risks for clothianidin and imidacloprid exceeded 5% for all endpoints, and exposure risk for chlorantraniliprole was below 5% for all endpoints. In field crops, risk to ground-nesting bees was high from clothianidin in all exposure scenarios and high for thiamethoxam and imidacloprid under chronic exposure scenarios. Risk assessments for ground-nesting bees should include exposure impacts from pesticides in soil and could use the hoary squash bee as an ecotoxicology model.


Assuntos
Agricultura , Abelhas/fisiologia , Inseticidas/toxicidade , Comportamento de Nidação/fisiologia , Medição de Risco , Solo/química , Animais , Produtos Agrícolas/parasitologia , Cucurbita/parasitologia , Exposição Ambiental , Praguicidas/toxicidade , Probabilidade
5.
Plant Dis ; 103(6): 1383-1390, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30958108

RESUMO

Interspecific hybrid squash (Cucurbita maxima × Cucurbita moschata) rootstocks used to graft watermelon (Citrullus lanatus var. lanatus) are resistant to Fusarium oxysporum f. sp. niveum, the fungus that causes Fusarium wilt of watermelon, but they are susceptible to Meloidogyne incognita, the southern root knot nematode. A new citron (Citrullus amarus) rootstock cultivar Carolina Strongback is resistant to F. oxysporum f. sp. niveum and M. incognita. The objective of this study was to determine if an interaction between M. incognita and F. oxysporum f. sp. niveum race 2 occurred on grafted or nongrafted triploid watermelon susceptible to F. oxysporum f. sp. niveum race 2. In 2016 and 2018, plants of nongrafted cultivar Fascination and Fascination grafted onto Carolina Strongback and interspecific hybrid squash cultivar Carnivor were inoculated or not inoculated with M. incognita before transplanting into field plots infested or not infested with F. oxysporum f. sp. niveum race 2. Incidence of Fusarium wilt and area under the disease progress curve did not differ when hosts were inoculated with F. oxysporum f. sp. niveum alone or F. oxysporum f. sp. niveum and M. incognita together. Fusarium wilt was greater on nongrafted watermelon (78% mean incidence) than on both grafted rootstocks and lower on Carnivor (1% incidence) than on Carolina Strongback (12% incidence; P ≤ 0.01). Plants not inoculated with F. oxysporum f. sp. niveum did not wilt. At the end of the season, Carnivor had a greater percentage of the root system galled than the other two hosts, whereas galling did not differ on Fascination and Carolina Strongback. F. oxysporum f. sp. niveum reduced marketable weight of nongrafted Fascination with and without coinoculation with M. incognita. M. incognita reduced marketable weight of Fascination grafted onto Carnivor compared with noninoculated, nongrafted Fascination. In conclusion, cucurbit rootstocks that are susceptible and resistant to M. incognita retain resistance to F. oxysporum f. sp. niveum when they are coinfected with M. incognita.


Assuntos
Cucurbita , Resistência à Doença , Fusarium , Infecções por HIV , Tylenchoidea , Animais , Cucurbita/microbiologia , Cucurbita/parasitologia , Fusarium/fisiologia , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Tylenchoidea/fisiologia
6.
J Chem Ecol ; 45(3): 313-325, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30706281

RESUMO

Although crop wild ancestors are often reservoirs of resistance traits lost during domestication, examining diverse cultivated germplasm may also reveal novel resistance traits due to distinct breeding histories. Using ten cultivars from two independent domestication events of Cucurbita pepo (ssp. pepo and texana), we identified divergences in constitutive and induced resistance measured by growth of generalist caterpillars and leaf traits. C. p. texana cultivars were consistently more resistant to Trichoplusia ni and Spodoptera exigua, and this was not due to expected mechanisms including cucurbitacins, nitrogen, sticky phloem sap, or toxicity. Although more susceptible on average, C. p. pepo cultivars showed stronger induced resistance, suggesting a trade-off between constitutive and induced resistance. To test the hypothesis that leaf volatiles accounted for differences in resistance to caterpillars, we devised a novel method to evaluate resistance on artificial diet while larvae are exposed to leaf volatiles. In both subspecies, cultivar-specific induced volatiles that reduced T. ni growth were present in highly inducible cultivars, but absent in those that showed no induction. These results have important agricultural implications as cultivar-specific resistance to caterpillars mirrored that of specialist beetles from field trials. Overall, the eponymous cucurbitacin defenses of the Cucurbitaceae are not the mechanistic basis of differences in constitutive or induced resistance between C. pepo subspecies or cultivars. Instead, deterrent cultivar-specific volatiles appear to provide general resistance to insect herbivores. Divergence during breeding history within and between subspecies revealed this pattern and novel resistance mechanism, defining new targets for plant breeding.


Assuntos
Cucurbita/parasitologia , Herbivoria , Insetos/fisiologia , Animais , Folhas de Planta/parasitologia
7.
Plant Cell Environ ; 40(11): 2780-2789, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28779505

RESUMO

Cucurbits have long been known to possess two types of phloem: fascicular (FP) within vascular bundles and extrafascicular phloem (EFP) surrounding vascular bundles and scattered through the cortex. Recently, their divergent composition was revealed, with FP having high sugar content consistent with conventional phloem, but EFP having much lower sugar levels and a very different proteome. However, the evolutionary advantages of possessing both FP and EFP have remained unclear. Here, we present four lines of quantitative evidence that together support the hypothesis that FP represents a typical phloem and is an attractive diet for aphids, whereas aphids avoid feeding on EFP. First, aphid stylet track endings were more abundant near the abaxial FP element of minor veins, suggesting a feeding preference for FP over EFP. Second, sugar profiles from stylet exudates were wholly consistent with FP origins, further supporting preference for FP and avoidance of EFP. Third, supplementation of EFP exudate into artificial diets confirmed an aversion to EFP in choice experiments. Finally, EFP exudate had negative effects on aphid performance. On the basis of aphids' inability to thrive on EFP, we conclude that EFP is atypical and perhaps should not be classed as a phloem system.


Assuntos
Cucurbita/parasitologia , Comportamento Alimentar , Floema/parasitologia , Animais , Dieta , Exsudatos de Plantas/metabolismo , Folhas de Planta/parasitologia , Feixe Vascular de Plantas/fisiologia , Açúcares/análise
8.
Turkiye Parazitol Derg ; 41(2): 92-95, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28695832

RESUMO

OBJECTIVE: Mites are microscopic organisms that lower the quality of life of people who are sensitive to them by causing conditions such as atopic dermatitis, allergic rhinitis, and asthma. These organisms are found in every habitat where humans live. This study was conducted to determine the presence of storage mites in dry food items. METHODS: Various food items were procured 10 times each in 300-gram samples. Mites were extracted with a Berlese funnel apparatus over Erlenmeyer flasks containing 70% alcohol placed at the end of the funnel stems for over 48 h. RESULTS: Of 25 food items examined in the study, only six were contaminated by mites. Species of the mites found were Acarus siro (34.6%), Glycyphagus domesticus (22.8%), Tyrophagus putrescentiae (16.8%), Tyrophagus spp. (7.9%), Rhizoglyphus spp. (1%), Lepidoglyphus destructor (7.9%), Cheylettus malacensis (4%), and Cheylettus spp. (2%). CONCLUSION: Although the results of the study show that the presence of mites in food items sold in open containers at open-air markets or stores was low, we suppose that they can cause important health problems for sensitive people.


Assuntos
Parasitologia de Alimentos , Ácaros/fisiologia , Animais , Asma/parasitologia , Cucurbita/parasitologia , Dermatite Atópica/parasitologia , Fibras na Dieta/parasitologia , Farinha/parasitologia , Armazenamento de Alimentos , Humanos , Masculino , Ácaros/classificação , Qualidade de Vida , Rinite Alérgica/parasitologia , Sementes/parasitologia , Triticum/parasitologia , Zea mays/parasitologia
9.
PLoS One ; 12(5): e0177981, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28545139

RESUMO

The host plant expansion of host-specialized Aphis gossypii (Glover) has been well studied in the laboratory; however, this phenomenon is poorly understood in the field. Here, we provide a series of laboratory and field experiments to assess the role of zucchini in the host plant expansion of cotton-specialized aphids. We observed that cotton-specialized aphids possessed the ability to expand on a new host plant (cucumber), with individuals first recorded on June 12 and consequently increasing exponentially in number in a field cage. A bioassay experiment showed that aphids from both cotton and cucumber preferred their natal host, but clones from zucchini have a stronger preference for cucumber than cotton or zucchini. A total of 1512 individuals were collected from a cotton field (mixed cotton and cucurbit plot), cotton farmland (cotton alone) and a field cage and sequenced to identify their biotypes. The results for apterous individuals from the cotton field showed that more cucurbit-specialized biotypes occurred on cucumber and more cotton-specialized biotypes occurred on cotton and zucchini. A majority (> 97.0%) of aphids from both the field cage and cotton farmland were cotton-specialized individuals. Consequently, eliminating intermediate host plants may be an effective measure to suppress A. gossypii outbreaks, because cotton and cucumber are often grown together in fields and greenhouses.


Assuntos
Afídeos/fisiologia , Cucumis sativus/parasitologia , Cucurbita/parasitologia , Gossypium/parasitologia , Agricultura/métodos , Animais , Especificidade de Hospedeiro , Interações Hospedeiro-Parasita , Dinâmica Populacional
10.
In Vitro Cell Dev Biol Anim ; 53(5): 417-420, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28205141

RESUMO

The squash bug, Anasa tristis, is a pest of cucurbits that exerts direct damage on crops and is a vector of plant pathogens. We established cell lines from this insect to serve as tools for basic biology, including virology and immunology, as well as applied studies, such as insecticide development programs. We initiated 15 cell cultures, using nine media or combinations of media. The media yielding the best results were a modification of Kimura's medium and a combination of two commercially available cell culture media (EX-CELL 420 and L15). We designated the two cell lines as BCIRL-AtE-CLG11 and BCIRL-AtE-CLG15. From the AtE-CLG15 line, we isolated two sub-lines, A and B. Of these, the most consistently replicating line was AtE-CLG15A. We determined the doubling time of this line (190 h) and its mean cell diameter (14.5 ± 0.7 µm). We characterized the AtE-CLG15A line using DAF-PCR. The BCIRL-AtE-CLG15A cell line is now available for researchers world-wide.


Assuntos
Linhagem Celular/citologia , Hemípteros/citologia , Hemípteros/efeitos dos fármacos , Inseticidas/farmacologia , Animais , Linhagem Celular/efeitos dos fármacos , Cucurbita/parasitologia , Hemípteros/patogenicidade , Estações do Ano
11.
Zootaxa ; 4184(3): zootaxa.4184.3.5, 2016 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-27988776

RESUMO

A new species of the family Alloionematidae was isolated from a rotten winged gourd at White Crane Garden, San Francisco, USA, sampled by Christopher Nelson in November 2010, and a live culture is deposited in Félix Lab Strain Database (http://www.justbio.com/worms/index.php), IBENS, Paris, France. Specimens from the culture have been examined. Both morphologically and molecularly, the nematode described herein as Alloionema californicum n. sp. differs from the other alloionematid species, A. appendiculatum and Neoalloionema tricaudatum. It is characterised by having a narrow stoma, 2.5-3.5 or 4 times longer than broad in adults or dauer juveniles respectively. Lateral fields are not present in adults but occur as one prominent ridge in dauers. Males have no bursa, six pairs of genital papillae and one single papilla. Dauers have large apparent phasmids in the middle of the tail. The ecology of the newly described species is unknown but probably it is a saprobic bacteriophagous nematode preferring rotting organic material.


Assuntos
Cucurbita/parasitologia , Doenças das Plantas/parasitologia , Rabditídios/classificação , Animais , Feminino , Masculino , Filogenia , Rabditídios/genética , Rabditídios/isolamento & purificação , Rabditídios/ultraestrutura , Análise de Sequência de DNA , Estados Unidos
12.
Bull Entomol Res ; 106(2): 191-6, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26693799

RESUMO

Silverleaf whitefly (SLW, Bemisia tabaci MEAM1) and aphids are sap-sucking insects, which pose a serious threat to Australian cucurbit crops and the horticulture industry. Traditional chemical control for these insect pests is becoming less effective, and there is a need to search for alternative or supplementary methods. This study aimed to manipulate the habitat of pumpkin crops in a tropical setting (Queensland, Australia), by growing pumpkins (var. Japanese pumpkin) alone and between lablab (Lablab purpureus L. Sweet). It was hypothesized that the presence of lablab will increase the populations of natural enemies, and through their control of insect pests such as SLW and aphids, will affect pumpkin yield. The population of arthropods (natural enemies and pests of pumpkin), with a focus on SLW and aphids, were sampled weekly on both lablab and pumpkin crop for a total of 21 weeks. Results showed that lablab hosted more enemies of SLW per plant than pumpkin in either treatment. In addition, adult SLW numbers were significantly higher in the pumpkin-only crop compared with the pumpkin grown between lablab, while pumpkin in the mixed plantings had significantly more ladybirds and lacewing larvae (P < 0.05). While there was no significant difference in the average fruit weight between treatments, the total weight (kg) and number of marketable pumpkins per hectare was greater (P < 0.05) for the pumpkin/lablab treatment than the pumpkin-only treatment. This study shows that growing lablab alongside a pumpkin crop may enhance natural enemies of SLW and could significantly increase the yield.


Assuntos
Cucurbita/parasitologia , Fabaceae/fisiologia , Hemípteros/fisiologia , Controle Biológico de Vetores/métodos , Animais , Afídeos/fisiologia , Cucurbita/efeitos dos fármacos , Cucurbita/crescimento & desenvolvimento , Ecossistema , Queensland
13.
Pest Manag Sci ; 72(7): 1335-9, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26388111

RESUMO

BACKGROUND: Zucchini squash, Cucurbita pepo L., is an important vegetable crop in Florida. Physiological disorders and insect-transmitted diseases are major problems for squash growers in semi-tropical regions around the world. Bemisia tabaci (Gennadius) biotype B is a significant whitefly pest and is largely responsible for transmitting viruses and causing physiological disorders in squash. Several studies have shown that whitefly populations are reduced when crops are interplanted with non-host cover crops or mulches. The aim of the present study was to determine how the presence of buckwheat, Fagopyrum esculentum Moench, and a key predator, Delphastus catalinae (Horn), affect whitefly colonization on squash. RESULTS: Whitefly densities were higher on squash than on buckwheat. The introduction of D. catalinae on squash significantly reduced whitefly populations. Overall, there were higher densities of D. catalinae on squash where the whitefly pest was more concentrated compared with buckwheat. CONCLUSION: The study provided preliminary evidence that D. catalinae, when used in conjunction with buckwheat as a living mulch, may aid in reducing whiteflies in squash. This greenhouse experiment highlights the need to investigate a multitactic approach of intercropping buckwheat with squash and the incorporation of D. catalinae in the field to manage populations of whiteflies and whitefly-transmitted diseases. © 2015 Society of Chemical Industry.


Assuntos
Besouros/fisiologia , Cucurbita , Fagopyrum , Hemípteros/fisiologia , Controle Biológico de Vetores/métodos , Animais , Proteção de Cultivos/métodos , Cucurbita/parasitologia , Fagopyrum/parasitologia
14.
Sci Rep ; 5: 10963, 2015 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-26043237

RESUMO

Plant viruses can profoundly alter the phenotypes of their host plants, with potentially far-reaching implications for ecology. Yet few studies have explored the indirect, host-mediated, effects of plant viruses on non-vector insects. We examined how infection of Cucurbita pepo plants by Cucumber mosaic virus (CMV) impacted the susceptibility of aphids (Myzus persicae) to attack by the parasitoid wasp Aphidius colemani. In semi-natural foraging assays, we observed higher rates of aphid parasitism on infected plants compared to healthy plants. Subsequent experiments revealed that this difference is not explained by different attack rates on plants differing in infection status, but rather by the fact that parasitoid larvae successfully complete their development more often when aphid hosts feed on infected plants. This suggests that the reduced nutritional quality of infected plants as host for aphids--documented in previous studies--compromises their ability to mount effective defenses against parasitism. Furthermore, our current findings indicate that the aphid diet during parasitoid development (rather than prior to wasp oviposition) is a key factor influencing resistance. These findings complement our previous work showing that CMV-induced changes in host plant chemistry alter patterns of aphid recruitment and dispersal in ways conducive to virus transmission.


Assuntos
Afídeos/fisiologia , Cucumovirus/fisiologia , Cucurbita/parasitologia , Cucurbita/virologia , Interações Hospedeiro-Parasita , Interações Hospedeiro-Patógeno , Doenças das Plantas/parasitologia , Doenças das Plantas/virologia , Animais , Suscetibilidade a Doenças
15.
Fungal Genet Biol ; 71: 21-31, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25151531

RESUMO

The powdery mildew fungi are obligate biotrophic plant pathogens that develop a specialized structure for parasitism termed haustorium, which is responsible for nutrient uptake and factor exchange with the plant. In this work, we present a detailed microscopy analysis of the haustoria of the cucurbit powdery mildew fungus Podosphaera xanthii, a major limiting factor for cucurbit production worldwide. Despite being located inside plant epidermal cells, transmission electron microscopy (TEM) analysis showed the characteristic highly irregular outline of the extrahaustorial membrane that separates the extrahaustorial matrix of haustoria from the cytoplasm of the plant cell. TEM analysis also revealed the presence of some vesicles and electron-dense plaques of material surrounding the haustoria. In confocal microscopy analysis and aniline blue staining we found a positive correlation between haustorial development and deposition of callose, which is distributed as plaques around haustorial complex. In this study, a method for the isolation of P. xanthii haustoria was also adapted, which permitted the analysis of the formation of haustorial lobes and the visualization of vacuoles and the pool of vesicles inside the haustorial complex. Our findings suggested that the haustorial lobes were responsible for vesicular trafficking and most likely act as the main mediators of the fungus-plant dialogue. All of these findings were integrated into a model of the P. xanthii-host cellular interactions.


Assuntos
Ascomicetos/fisiologia , Cucurbita/parasitologia , Doenças das Plantas/parasitologia , Ascomicetos/metabolismo , Ascomicetos/ultraestrutura , Cucurbita/citologia , Glucanos/metabolismo , Hifas/metabolismo , Hifas/fisiologia , Hifas/ultraestrutura , Folhas de Planta/citologia , Folhas de Planta/parasitologia
16.
Virus Res ; 186: 135-43, 2014 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-24486486

RESUMO

Zucchini yellow mosaic virus (ZYMV, genus Potyvirus) causes important crop losses in cucurbits worldwide. In France, ZYMV epidemics are sporadic but occasionally very severe. This contrasts with Watermelon mosaic virus (WMV, genus Potyvirus) which causes regular and early epidemics. Factors influencing ZYMV epidemiology are still poorly understood. In order to gain new insights on the ecology and epidemiology of this virus, a 5-year multilocation trial was conducted in which ZYMV spread and populations were studied in each of the 20 plot/year combinations and compared with WMV. Search for ZYMV alternative hosts was conducted by testing weeds growing naturally around one plot and also by checking ZYMV natural infections in selected ornamental species. Although similar ZYMV populations were observed occasionally in the same plot in two successive years suggesting the occurrence of overwintering hosts nearby, only two Lamium amplexicaule plants were found to be infected by ZYMV of 3459 weed samples that were tested. The scarcity of ZYMV reservoirs contrasts with the frequent detection of WMV in the same samples. Since ZYMV and WMV have many aphid vectors in common and are transmitted with similar efficiencies, the differences observed in ZYMV and WMV reservoir abundances could be a major explanatory factor for the differences observed in the typology of ZYMV and WMV epidemics in France. Other potential ZYMV alternative hosts have been identified in ornamental species including begonia. Although possible in a few cases, exchanges of populations between different plots located from 500 m to 4 km apart seem uncommon. Therefore, the potential dissemination range of ZYMV by its aphid vectors seems to be rather limited in a fragmented landscape.


Assuntos
Citrullus/virologia , Cucurbita/virologia , Filogenia , Doenças das Plantas/virologia , Potyvirus/genética , RNA Viral/genética , Animais , Afídeos/fisiologia , Comportamento Animal , Citrullus/parasitologia , Cucurbita/parasitologia , Comportamento Alimentar , França , Haplótipos , Especificidade de Hospedeiro , Interações Hospedeiro-Parasita , Insetos Vetores/fisiologia , Epidemiologia Molecular , Filogeografia , Doenças das Plantas/parasitologia , Plantas Daninhas/parasitologia , Plantas Daninhas/virologia , Potyvirus/classificação , Potyvirus/isolamento & purificação
17.
Sci Rep ; 4: 4155, 2014 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-24561664

RESUMO

The dynamics of association between pathogens and vectors can strongly influence epidemiology. It has been proposed that wilt disease epidemics in cucurbit populations are sustained by persistent colonization of beetle vectors (Acalymma vittatum) by the bacterial phytopathogen Erwinia tracheiphila. We developed a qPCR method to quantify E. tracheiphila in whole beetles and frass and used it to assess pathogen acquisition and retention following variable exposure to infected plants. We found that (i) E. tracheiphila is present in frass in as little as three hours after feeding on infected plants and can be transmitted with no incubation period by vectors given brief exposure to infected plants, but also by persistently colonized vectors several weeks following exposure; (ii) duration of exposure influences rates of long-term colonization; (iii) frass infectivity (assessed via inoculation experiments) reflects bacterial levels in frass samples across time; and (iv) vectors rarely clear E. tracheiphila infections, but suffer no apparent loss of fitness. These results describe a pattern conducive to the effective maintenance of E. tracheiphila within cucurbit populations.


Assuntos
Vetores Artrópodes/microbiologia , Besouros/microbiologia , Doenças das Plantas/microbiologia , Animais , Cucurbita/microbiologia , Cucurbita/parasitologia , Erwinia/genética , Erwinia/isolamento & purificação , Erwinia/fisiologia , Interações Hospedeiro-Patógeno , Folhas de Planta/microbiologia , Folhas de Planta/parasitologia , RNA Ribossômico 18S/metabolismo
18.
Ying Yong Sheng Tai Xue Bao ; 24(5): 1435-8, 2013 May.
Artigo em Chinês | MEDLINE | ID: mdl-24015567

RESUMO

A comparative study was conducted on the life table parameters of Aphis gossypii reared on five host plant species at (25 +/- 1) degrees C in laboratory. There existed significant differences in the durations of various developmental stages, adult longevity, mean offspring number per day, net reproductive rate, intrinsic rate of increase, finite rate of increase, mean generation time, and population doubling time for the A. gossypii populations reared on the host plants. For the aphids on Lagenaria siceraria var. turbinate, they needed the longest time (5.84 days) to complete one generation, but for those on the other four plants, no significant differences were observed, with the time needed ranged from 5.24 to 5.45 days. The adult longevity was the longest (20.04 days) on Cucumis sativus, but had no significant differences on the other four host plants, being from 14.76 to 16.03 days. The populations' survival curves on all test host plants were of Deevey I, i. e., the death mainly occurred during late period. The survival rate on C. sativus was higher than those on the other four host plants. Based on the intrinsic rates of increase of A. gossypii, its host suitability was in the order of Cucumis melo var. saccharinus > Lagenaria siceraria var. turbinate > Cucurbita moschata var. melonaeformis > Cucumis sativus > Cucurbita pepo var. medullosa.


Assuntos
Afídeos/fisiologia , Cucumis sativus/parasitologia , Interações Hospedeiro-Parasita , Reprodução/fisiologia , Animais , Afídeos/crescimento & desenvolvimento , Cucumis melo/parasitologia , Cucurbita/parasitologia , Gossypium/parasitologia , Dinâmica Populacional
19.
Ecology ; 93(2): 430-5, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22624324

RESUMO

Many organisms face challenges in avoiding predation while searching for mates. For plants, emitting floral fragrances to advertise reproductive structures could increase the attraction of detrimental insects along with pollinators. Very few studies have experimentally evaluated the costs and benefits of fragrance emission with explicit consideration of how plant fitness is affected by both pollinators and florivores. To determine the reproductive consequences of increasing the apparency of reproductive parts, we manipulated fragrance, pollination, and florivores in the wild Texas gourd, Cucurbita pepo var. texana. With enhanced fragrance we found an increase in the attraction of florivores, rather than pollinators, and a decrease in seed production. This study is the first to demonstrate that enhanced floral fragrance can increase the attraction of detrimental florivores and decrease plant reproduction, suggesting that florivory as well as pollination has shaped the evolution of floral scent.


Assuntos
Besouros/efeitos dos fármacos , Besouros/fisiologia , Cucurbita/fisiologia , Cucurbita/parasitologia , Flores , Odorantes , Animais , Comportamento Animal , Reprodução/fisiologia
20.
Multimed ; 16(4)2012. tab
Artigo em Espanhol | CUMED | ID: cum-57173

RESUMO

Se realizó un estudio descriptivo, transversal en el consultorio médico de la comunidad del Zamuro, parroquia San Rafael, municipio Tucupita, estado Delta Amacuro, el universo lo constituyeron los niños comprendidos entre los grupos etáreos de 5 a 9 años, la muestra quedó constituida por 112, que acudieron a la consulta con manifestaciones clínicas de parasitismo intestinal producido por helmintos, se excluyeron 28 que no cumplieron criterios de inclusión, los pacientes se seleccionaron de forma aleatoria simple, con el objetivo de demostrar el comportamiento del tratamiento con la semilla de calabaza en esta enfermedad parasitaria, en el período comprendido de enero a julio del 2012 . Predominó el sexo masculino, se obtuvo la curación en niños a los que se les aplicó el tratamiento con la semilla de calabaza y se demostró la inocuidad y efectividad del tratamiento, para ello se realizó una comparación clínica utilizando la variable tiempo, antes y después del tratamiento(AU)


It was performed a descriptive, transversal study in the medical office at Zamuro community, Saint Rafael parish, Tucupita, in Delta Amacuro state, the universe was made by the children between the etharian groups of 5 to 9 years old, the sample consisted on 112 children that came to the consult with clinical manifestations of intestinal parasitism produced by helminths, there were excluded 28 of them that did not fulfill the inclusion criteria, the patients were selected at random with the objective to show the behavior of the treatment with the pumpkin seeds for this parasitic illness, during the period between January to July, 2012. The male sex prevailed, obtaining the healing in children after the application of the treatment with the seed of pumpkin and it was evidenced the inocuity and effectiveness of the treatment, for that purpose it was performed a clinical comparison using the variable of time, before and after the treatment(EU)


Assuntos
Cucurbita/parasitologia , Fitoterapia , Plantas Medicinais , Epidemiologia Descritiva , Estudos Transversais
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