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1.
J Therm Biol ; 72: 53-58, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29496015

RESUMO

The pea aphid Acyrthosiphon pisum is a common pest of many species of legumes and its parasitoid Aphidius ervi is regarded as a successful biocontrol agent. In this study, we report a greater survival rate of parasitized aphids compared with unparasitized ones, after exposure to a very high temperature (39°C for 30min). After the heat shock, the survival of unparasitized aphids decreases according to their age at the heat shock treatment, suggesting a different adaptation of the aphid life stage to the different microclimatic conditions they experience. Survival of parasitized aphids does not change according to the time of the heat shock treatment, but it is always significantly higher compared with the unparasitized ones. Parasitized aphids are very quickly subjected to a wide range of physiological modifications and the observed increased survival could be a consequence of these modifications before the heat shock treatment. The possible explanations as well as the possible adaptive nature of the observed phenomenon are discussed.


Assuntos
Afídeos/fisiologia , Resposta ao Choque Térmico , Vespas/fisiologia , Animais , Afídeos/parasitologia , Feminino , Temperatura Alta , Taxa de Sobrevida
2.
Curr Res Insect Sci ; 5: 100081, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38694273

RESUMO

The changing environmental conditions can affect insect biology over multiple generations and phenotypic plasticity is important for coping with these changes. Transgenerational plasticity occurs when the environment in which the parents developed influences the plastic response of the offspring phenotype. In the present study, the plastic effects of resource limitation on important life history traits such as body size, fecundity, survival, and resistance to starvation of the pea aphid Acyrthosiphon pisum were investigated over two generations. This study focused on understanding how resource limitation can determine an adaptive expression of maternal effects and transgenerational plasticity in fitness-related traits. Aphids showed phenotypic plasticity for the life history traits investigated, as they performed better when grown in an optimal environment than in a resource-poor one. Also, aphids had a poorer performance if their mothers were raised in a resource-poor environment. The effects of transgenerational plasticity were observed only in response to resistance to starvation, through increased survival in the offspring of the mother reared in a resource-poor environment, suggesting an evolutionary bet-hedging strategy. The results of this study showed that the effects of adaptive transgenerational plasticity may be partially masked in stressful environments, where developmental problems instead predominate. More information on the transgenerational response to resource limitation across generations can contribute to a better understanding of aphid biology.

3.
Environ Sci Pollut Res Int ; 31(12): 18887-18899, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38353820

RESUMO

The scarcity of freshwater for agriculture in many regions has led to the application of sewage and saline water for irrigation. Irrigation with non-conventional water sources could become a non-harmful process for plant cultivation, and the effects of their use on crops should be monitored in order to develop optimal management strategies. One possibility to overcome potential barriers is to use biostimulants such as Trichoderma spp. fungi. Tomato is a crop of great economic importance in the world. This study investigated the joint effects of Trichoderma afroharzianum T-22 on tomato plants irrigated with simulated unconventional waters. The experiment consisted of a control and three water treatments. In the control, the plants were watered with distilled water. The three water treatments were obtained by using an irrigation water added with nitrogen, a wastewater effluent, and a mixed groundwater-wastewater effluents. Potted tomato plants (variety Bobcat) were grown in a controlled growth chamber. Antioxidant activity, susceptibility to the aphids Macrosiphum euphorbiae, and tomato plant growth parameters were estimated. Trichoderma afroharzianum T-22 had a positive effect on plant growth and antioxidant defenses when plants were irrigated with distilled water. Instead, no significant morphological effects induced by T. afroharzianum T-22 on plants were observed when unconventional water was used for irrigation. However, inoculation with T. afroharzianum T-22 activated a stress response that made the colonized plants more susceptible to aphid development and increased their fecundity and longevity. Thanks to this study, it may be possible for the first time to open a new discussion on the practical possibility of using reclaimed wastewater for crop irrigation with the addition of a growth-promoting fungal symbiont.


Assuntos
Afídeos , Hypocreales , Solanum lycopersicum , Trichoderma , Animais , Águas Residuárias , Afídeos/fisiologia , Antioxidantes , Trichoderma/fisiologia , Irrigação Agrícola
4.
Mol Plant Microbe Interact ; 26(10): 1249-56, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23718124

RESUMO

Below ground and above ground plant-insect-microorganism interactions are complex and regulate most of the developmental responses of important crop plants such as tomato. We investigated the influence of root colonization by a nonmycorrhizal plant-growth-promoting fungus on direct and indirect defenses of tomato plant against aphids. The multitrophic system included the plant Solanum lycopersicum ('San Marzano nano'), the root-associated biocontrol fungus Trichoderma longibrachiatum strain MK1, the aphid Macrosiphum euphorbiae (a tomato pest), the aphid parasitoid Aphidius ervi, and the aphid predator Macrolophus pygmaeus. Laboratory bioassays were performed to assess the effect of T. longibrachiatum MK1, interacting with the tomato plant, on quantity and quality of volatile organic compounds (VOC) released by tomato plant, aphid development and reproduction, parasitoid behavior, and predator behavior and development. When compared with the uncolonized controls, plants whose roots were colonized by T. longibrachiatum MK1 showed quantitative differences in the release of specific VOC, better aphid population growth indices, a higher attractiveness toward the aphid parasitoid and the aphid predator, and a quicker development of aphid predator. These findings support the development of novel strategies of integrated control of aphid pests. The species-specific or strain-specific characteristics of these below ground-above ground interactions remain to be assessed.


Assuntos
Afídeos/fisiologia , Himenópteros/fisiologia , Controle Biológico de Vetores , Doenças das Plantas/microbiologia , Solanum lycopersicum/microbiologia , Trichoderma/fisiologia , Animais , Interações Hospedeiro-Patógeno , Solanum lycopersicum/química , Solanum lycopersicum/parasitologia , Doenças das Plantas/parasitologia , Raízes de Plantas/química , Raízes de Plantas/microbiologia , Raízes de Plantas/parasitologia , Especificidade da Espécie , Compostos Orgânicos Voláteis/metabolismo
5.
Insects ; 13(5)2022 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-35621754

RESUMO

Fungi belonging to the genus Trichoderma have received much attention in recent years due to their beneficial effects on crop health and their use as pest control agents. Trichoderma activates direct plant defenses against phytophagous arthropods and reinforces indirect plant defense through the attraction of predators. Although the plant defenses against insect herbivores were demonstrated in laboratory experiments, little attention has been paid to the use of Trichoderma spp. in open field conditions. In the present study, we investigated the effects of the inoculation of the commercial Trichoderma harzianum strain T22 on the arthropod community associated with tomato plants and on the crop performance in an experimental field located in South Italy. Our results showed that inoculation with T. harzianum could alter the arthropod community and reduce the abundance of specific pests under field conditions with respect to the sampling period. The present study also confirmed the beneficial effect of T. harzianum against plant pathogens and on tomato fruit. The complex tomato-arthropod-microorganism interactions that occurred in the field are discussed to enrich our current information on the possibilities of using Trichoderma as a green alternative agent in agriculture.

6.
Microorganisms ; 10(11)2022 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-36422311

RESUMO

Agrochemicals are generally used in agriculture to maximize yields and product quality, but their overuse can cause environmental pollution and human health problems. To reduce the off-farm input of chemicals, numerous biostimulant products based on beneficial symbiont plant fungi are receiving a great deal of attention. The evolution of plant diseases and the performance of insects are influenced by plant chemical defences, both of which are, in turn, influenced by below-ground symbionts. Direct and indirect plant defences mediated by belowground symbionts against plant diseases and insect herbivores were demonstrated in greenhouses experiments. However, little attention has been paid to the use of Trichoderma under open field conditions, and no data are available for zucchini (Cucurbita pepo L.) plants in the field. To determine the effects of a commercial Trichoderma harzianum strain T22 on plant viruses, powdery mildew, the arthropod community, and on the agronomic performance associated with zucchini plants, an experiment was conducted in 2022 under open field conditions in South Italy. Our results indicate that T. harzianum T22 makes zucchini plants more attractive to aphids and to Hymenoptera parasitoid but failed to control zucchini pathogens. The complex plant-disease-arthropod-microorganism interactions that occurred in the field during the entire plant cycle are discussed to enrich our current information on the possibilities of using these microorganisms as a green alternative in agriculture.

7.
Biotech Histochem ; 94(2): 108-114, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30354692

RESUMO

Although hematoxylin and eosin (H & E) staining of sectioned embryonic insect material is widely used, it is time-consuming and may not provide sufficient information. We evaluated new staining procedures for embryonic whole mounts of the greater wax moth, Galleria mellonella. We compared a combination of toluidine blue and rhodamine B (TB-RB) to H & E; we also investigated calcofluor white (CFW) staining. TB-RB staining produced staining similar to H & E. TB-RB staining was less time-consuming and improved visualization of the blastoderm and its differentiation into the germ disk and serosa membrane. CFW enhanced details of mitosis in nuclei post-fertilization and stained the primary serosal membrane. Staining of whole mounts with TB-RB and CFW enabled embryonic staging that was more rapid, convenient and effective than the routine approach using H & E and fluorescent probes.


Assuntos
Mariposas , Rodaminas , Coloração e Rotulagem , Cloreto de Tolônio , Animais , Benzenossulfonatos , Hematoxilina , Coloração e Rotulagem/métodos
8.
PLoS One ; 7(3): e32759, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22427877

RESUMO

BACKGROUND: Aphids are agricultural pests of great economical interest. Alternatives to insecticides, using semiochemicals, are of difficult applications. In fact, sex pheromones are of little use as aphids reproduce partenogenetically most of the time. Besides, the alarm pheromone, (E)-ß-farnesene for a great number of species, is difficult to synthesize and unstable in the environment. The search for novel semiochemicals to be used in population control can be efficiently approached through the study of the olfactory system at the biochemical level. Recently odorant-binding proteins (OBPs) have been shown to play a central role in olfactory recognition, thus becoming the target of choice for designing new semiochemicals. METHODOLOGY/PRINCIPAL FINDINGS: To address the question of how the alarm message is recognised at the level of OBPs, we have tested 29 compounds, including (E)-ß-farnesene, in binding assays with 6 recombinant proteins and in behaviour experiments. We have found that good repellents bind OBP3 and/or OBP7, while non repellents present different spectra of binding. These results have been verified with two species of aphids, Acyrthosiphon pisum and Myzus persicae, both using (E)-ß-farnesene as the alarm pheromone. CONCLUSIONS: Our results represent further support to the idea (so far convincingly demonstrated only in Drosophila) that OBPs are involved in decoding the chemical information of odorants and pheromones, and for the first time provide such evidence in other insect species and using wild-type insects. Moreover, the data offer guidelines and protocols for the discovery of potential alarm pheromones, using ligand-binding assays as a preliminary screening before subjecting selected compounds to behaviour tests.


Assuntos
Afídeos/fisiologia , Reação de Fuga/fisiologia , Controle de Insetos/métodos , Modelos Moleculares , Percepção Olfatória/fisiologia , Receptores Odorantes/metabolismo , Sesquiterpenos/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Primers do DNA/genética , DNA Complementar/genética , Fluorescência , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Receptores Odorantes/química , Receptores Odorantes/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Análise de Sequência de DNA , Especificidade da Espécie
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