Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 24
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Mol Ecol Resour ; 21(7): 2437-2454, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34051038

RESUMO

Molecular identification is increasingly used to speed up biodiversity surveys and laboratory experiments. However, many groups of organisms cannot be reliably identified using standard databases such as GenBank or BOLD due to lack of sequenced voucher specimens identified by experts. Sometimes a large number of sequences are available, but with too many errors to allow identification. Here, we address this problem for parasitoids of Drosophila by introducing a curated open-access molecular reference database, DROP (Drosophila parasitoids). Identifying Drosophila parasitoids is challenging and poses a major impediment to realize the full potential of this model system in studies ranging from molecular mechanisms to food webs, and in biological control of Drosophila suzukii. In DROP, genetic data are linked to voucher specimens and, where possible, the voucher specimens are identified by taxonomists and vetted through direct comparison with primary type material. To initiate DROP, we curated 154 laboratory strains, 856 vouchers, 554 DNA sequences, 16 genomes, 14 transcriptomes, and six proteomes drawn from a total of 183 operational taxonomic units (OTUs): 114 described Drosophila parasitoid species and 69 provisional species. We found species richness of Drosophila parasitoids to be heavily underestimated and provide an updated taxonomic catalogue for the community. DROP offers accurate molecular identification and improves cross-referencing between individual studies that we hope will catalyse research on this diverse and fascinating model system. Our effort should also serve as an example for researchers facing similar molecular identification problems in other groups of organisms.


Assuntos
Biodiversidade , Drosophila , Animais , Drosophila/genética , Cadeia Alimentar
2.
Sci Rep ; 10(1): 3114, 2020 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-32080275

RESUMO

The meadow spittlebug, Philaenus spumarius, is a highly polyphagous widespread species, playing a major role in the transmission of the bacterium Xylella fastidiosa subspecies pauca, the agent of the "Olive Quick Decline Syndrome". Essential oils (EOs) are an important source of bio-active volatile compounds that could interfere with basic metabolic, biochemical, physiological, and behavioural functions of insects. Here, we report the electrophysiological and behavioural responses of adult P. spumarius towards some EOs and related plants. Electroantennographic tests demonstrated that the peripheral olfactory system of P. spumarius females and males perceives volatile organic compounds present in the EOs of Pelargonium graveolens, Cymbopogon nardus and Lavandula officinalis in a dose-dependent manner. In behavioral bioassays, evaluating the adult responses towards EOs and related plants, both at close (Y-tube) and long range (wind tunnel), males and females responded differently to the same odorant. Using EOs, a clear attraction was noted only for males towards lavender EO. Conversely, plants elicited responses that varied upon the plant species, testing device and adult sex. Both lavender and geranium repelled females at any distance range. On the contrary, males were attracted by geranium and repelled by citronella. Finally, at close distance, lavender and citronella were repellent for females and males, respectively. Our results contribute to the development of innovative tools and approaches, alternative to the use of synthetic pesticides, for the sustainable control of P. spumarius aiming to contrasting the expansion of X. fastidiosa.


Assuntos
Comportamento Animal , Fenômenos Eletrofisiológicos , Hemípteros/efeitos dos fármacos , Óleos Voláteis/farmacologia , Animais , Infecções Bacterianas/microbiologia , Bioensaio , Feminino , Repelentes de Insetos , Insetos Vetores/microbiologia , Masculino , Odorantes , Doenças das Plantas/microbiologia , Olfato , Compostos Orgânicos Voláteis/farmacologia , Xylella
3.
Plants (Basel) ; 8(10)2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31623335

RESUMO

Plant defense peptides represent an important class of compounds active against pathogens and insects. These molecules controlling immune barriers can potentially be used as novel tools for plant protection, which mimic natural defense mechanisms against invaders. The constitutive expression in tomato plants of the precursor of the defense peptide systemin was previously demonstrated to increase tolerance against moth larvae and aphids and to hamper the colonization by phytopathogenic fungi, through the expression of a wealth of defense-related genes. In this work we studied the impact of the exogenous supply of systemin to tomato plants on pests to evaluate the use of the peptide as a tool for crop protection in non-transgenic approaches. By combining gene expression studies and bioassays with different pests we demonstrate that the exogenous supply of systemin to tomato plants enhances both direct and indirect defense barriers. Experimental plants, exposed to this peptide by foliar spotting or root uptake through hydroponic culture, impaired larval growth and development of the noctuid moth Spodoptera littoralis, even across generations, reduced the leaf colonization by the fungal pathogen Botrytis cinerea and were more attractive towards natural herbivore antagonists. The induction of these defense responses was found to be associated with molecular and biochemical changes under control of the systemin signalling cascade. Our results indicate that the direct delivery of systemin, likely characterized by a null effect on non-target organisms, represents an interesting tool for the sustainable protection of tomato plants.

4.
Front Physiol ; 10: 813, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31333483

RESUMO

Numerous microbial root symbionts are known to induce different levels of enhanced plant protection against a variety of pathogens. However, more recent studies have demonstrated that beneficial microbes are able to induce plant systemic resistance that confers some degree of protection against insects. Here, we report how treatments with the fungal biocontrol agent Trichoderma atroviride strain P1 in tomato plants induce responses that affect pest insects with different feeding habits: the noctuid moth Spodoptera littoralis (Boisduval) and the aphid Macrosiphum euphorbiae (Thomas). We observed that the tomato plant-Trichoderma P1 interaction had a negative impact on the development of moth larvae and on aphid longevity. These effects were attributed to a plant response induced by Trichoderma that was associated with transcriptional changes of a wide array of defense-related genes. While the impact on aphids could be related to the up-regulation of genes involved in the oxidative burst reaction, which occur early in the defense reaction, the negative performance of moth larvae was associated with the enhanced expression of genes encoding for protective enzymes (i.e., Proteinase inhibitor I (PI), Threonine deaminase, Leucine aminopeptidase A1, Arginase 2, and Polyphenol oxidase) that are activated downstream in the defense cascade. In addition, Trichoderma P1 produced alterations in plant metabolic pathways leading to the production and release of volatile organic compounds (VOCs) that are involved in the attraction of the aphid parasitoid Aphidius ervi, thus reinforcing the indirect plant defense barriers. Our findings, along with the evidence available in the literature, indicate that the outcome of the tripartite interaction among plant, Trichoderma, and pests is highly specific and only a comprehensive approach, integrating both insect phenotypic changes and plant transcriptomic alterations, can allow a reliable prediction of its potential for plant protection.

5.
PLoS One ; 14(3): e0205475, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30883559

RESUMO

Scale insects (Hemiptera: Sternorrhyncha: Coccomorpha) are key pests of agricultural crops and ornamental plants worldwide. Their populations are difficult to control, even with insecticides, due to their cryptic habits. Moreover, there is growing concern over the use of synthetic pesticides for their control, due to deleterious environmental effects and the emergence of resistant populations of target pests. In this context, biological control may be an effective and sustainable approach. Hymenoptera Chalcidoidea includes natural enemies of scale insects that have been successfully used in many biological control programs. However, the correct identification of pest scale species and their natural enemies is particularly challenging because these insects are very small and highly specialized. Integrative taxonomy, coupling DNA barcoding and morphological analysis, has been successfully used to characterize pests and natural enemy species. In this study, we performed a survey of parasitoids and predators of armored and soft scales in Chile, based on 28S and COI barcodes. Fifty-three populations of Diaspididae and 79 populations of Coccidae were sampled over the entire length of the country, from Arica (18°S) to Frutillar (41°S), between January 2015 and February 2016. The phylogenetic relationships obtained by Bayesian inference from multilocus haplotypes revealed 41 putative species of Chalcidoidea, five Coccinellidae and three Neuroptera. Species delimitation was confirmed using ABGD, GMYC and PTP model. In Chalcidoidea, 23 species were identified morphologically, resulting in new COI barcodes for 12 species and new 28S barcodes for 14 species. Two predator species (Rhyzobius lophantae and Coccidophilus transandinus) were identified morphologically, and two parasitoid species, Chartocerus niger and Signiphora bifasciata, were recorded for the first time in Chile.


Assuntos
Código de Barras de DNA Taxonômico , Hemípteros/anatomia & histologia , Hemípteros/genética , Interações Hospedeiro-Parasita , Himenópteros/anatomia & histologia , Himenópteros/genética , Anacardiaceae/parasitologia , Animais , Teorema de Bayes , Chile , Haplótipos , Hemípteros/classificação , Filogenia
6.
PLoS One ; 13(11): e0205245, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30403678

RESUMO

Ooencyrtus spp. (Hymenoptera, Chalcidoidea, Encyrtidae) are important natural enemies of agricultural and forest insect pests, and are distributed worldwide. Their reduced dimensions, highly variable morphological characters and possible effect of wide host range and abiotic factors, make correct identification at the species level particularly difficult. This paper combined molecular, morphological, and biological data to characterize a group of Ooencyrtus spp. emerging from the eggs of the variegated caper bug, Stenozygum coloratum in the east Mediterranean area. COI and ITS2 sequencing revealed the presence of six and five divergent clades, respectively. Three clades were identified as Ooencyrtus telenomicida, Ooencyrtus pityocampae and O. pistaciae. Two clades represent new species which are here described and named Ooencyrtus zoeae and Ooencyrtus mevalbelus. These features were combined with reliable morphological characters to facilitate the separation of these species. A dichotomous key and a new synonymy are proposed. Ooencyrtus pistaciae had two distinct COI clades but only one ITS2 clade. Crossbreeding trials that included Ooencyrtus telenomicida, Ooencyrtus melvabelus sp. nov. and Ooencyrtus zoeae sp. nov. confirmed their reproductive isolation. COI sequences showed 0-0.8% and 4-9% within and between-species genetic differences, respectively. ITS2 showed 0.4-5.9% genetic differences between species, with no genetic differences within species. Haplotype diversity of Israeli and Turkish populations of the various species was 0-0.98 and was particularly low in Ooencyrtus pityocampae, whose Israeli population showed no diversity. The discovery of the Ooencyrtus spp. on the eggs of the caper bug, and their abundance support the idea that the bug can be used as an alternative host for augmentation of populations of these parasitoids in agricultural and forestry systems.


Assuntos
Biodiversidade , Hemípteros , Himenópteros , Animais , Cruzamento , Cruzamentos Genéticos , Ovos , Genes Mitocondriais , Variação Genética , Haplótipos , Hemípteros/anatomia & histologia , Hemípteros/classificação , Hemípteros/genética , Himenópteros/anatomia & histologia , Himenópteros/classificação , Himenópteros/genética , Filogenia
7.
Front Plant Sci ; 9: 1480, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30356724

RESUMO

Arbuscular mycorrhizal (AM) fungi are very widespread, forming symbiotic associations with ∼80% of land plant species, including almost all crop plants. These fungi are considered of great interest for their use as biofertilizer in low-input and organic agriculture. In addition to an improvement in plant nutrition, AM fungi have been reported to enhance plant tolerance to important abiotic and biotic environmental conditions, especially to a reduced availability of resources. These features, to be exploited and applied in the field, require a thorough identification of mechanisms involved in nutrient transfer, metabolic pathways induced by single and multiple stresses, physiological and eco-physiological mechanisms resulting in improved tolerance. However, cooperation between host plants and AM fungi is often related to the specificity of symbiotic partners, the environmental conditions and the availability of resources. In this study, the impact of two AM fungal species (Funneliformis mosseae and Rhizophagus intraradices) on the water stress tolerance of a commercial tomato cultivar (San Marzano nano) has been evaluated in pots. Biometric and eco-physiological parameters have been recorded and gene expression analyses in tomato roots have been focused on plant and fungal genes involved in inorganic phosphate (Pi) uptake and transport. R. intraradices, which resulted to be more efficient than F. mosseae to improve physiological performances, was selected to assess the role of AM symbiosis on tomato plants subjected to combined stresses (moderate water stress and aphid infestation) in controlled conditions. A positive effect on the tomato indirect defense toward aphids in terms of enhanced attraction of their natural enemies was observed, in agreement with the characterization of volatile organic compound (VOC) released. In conclusion, our results offer new insights for understanding the molecular and physiological mechanisms involved in the tolerance toward water deficit as mediated by a specific AM fungus. Moreover, they open new perspectives for the exploitation of AM symbiosis to enhance crop tolerance to abiotic and biotic stresses in a scenario of global change.

8.
Zootaxa ; 4444(3): 316-326, 2018 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-30313926

RESUMO

New additions to the Iranian fauna are reported. Three new species of Encyrtidae, Anagyrus osmoi sp. nov., Metaphycus prengoi sp. nov., and Microterys obricoi sp. nov., are described. Three new records, Anagyrus saccharicola Timberlake, 1932, Copidosoma filicorne (Dalman, 1820) and Paranathrix acanthococci (Myartseva, 1977) and one note are reported.


Assuntos
Himenópteros , Animais , Irã (Geográfico)
9.
Int J Mol Sci ; 19(9)2018 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-30217050

RESUMO

Following herbivore attacks, plants modify a blend of volatiles organic compounds (VOCs) released, resulting in the attraction of their antagonists. However, volatiles released constitutively may affect herbivores and natural enemies' fitness too. In tomato there is still a lack of information on the genetic bases responsible for the constitutive release of VOC involved in direct and indirect defenses. Here we studied the constitutive emissions related to the two most abundant sesquiterpene synthase genes expressed in tomato and their functional role in plant defense. Using an RNA interference approach, we silenced the expression of TPS9 and TPS12 genes and assessed the effect of this transformation on herbivores and parasitoids. We found that silenced plants displayed a different constitutive volatiles emission from controls, resulting in reduced attractiveness for the aphid parasitoid Aphidius ervi and in an impaired development of Spodoptera exigua larvae. We discussed these data considering the transcriptional regulation of key-genes involved in the pathway of VOC metabolism. We provide several lines of evidence on the metabolic flux from terpenoids to phenylpropanoids. Our results shed more light on constitutive defenses mediated by plant volatiles and on the molecular mechanisms involved in their metabolic regulation.


Assuntos
Herbivoria/fisiologia , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/parasitologia , Animais , Afídeos/fisiologia , Interações Hospedeiro-Parasita , Spodoptera/fisiologia , Compostos Orgânicos Voláteis/metabolismo , Vespas/fisiologia
10.
Zootaxa ; 4531(3): 374-382, 2018 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-30647395

RESUMO

Delottococcus aberiae is an invasive mealybug native to South Africa that has been accidentally introduced into Spain. A survey of natural enemies in its native area to potentially be used for biological control of this pest resulted in a number of species, among which four belonged to the genus Anagyrus. Following an integrative approach using morphological and molecular data, two species new to science are here described and compared with closely related ones: Anagyrus aberiae sp.n. and Anagyrus antoniae sp.n. A dichotomous key to separate the species of Anagyrus attacking D. aberiae in South Africa is provided. [Zoobank LSID: Anagyrus aberiae Guerrieri sp. nov. (Fig. 1-7): LSID urn:lsid:zoobank.org:pub:8CF8983B-93DC-4ECF-A8FB-CF76E94319B3 Anagyrus antoniae Guerrieri sp. nov. (Fig. 8-12): LSID urn:lsid:zoobank.org:pub:8CF8983B-93DC-4ECF-A8FB-CF76E94319B3].


Assuntos
Hemípteros , Himenópteros , Animais , África do Sul , Espanha
11.
Zootaxa ; 4527(2): 295-296, 2018 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-30651470

RESUMO

A correction to an oversight in a recently published checklist of Iranian species of Encyrtidae (Hymenoptera, Chalcidoidea) is presented, along with recommended amendments, resulting in 173 species belonging to 51 genera.


Assuntos
Himenópteros , Animais , Irã (Geográfico)
12.
Sci Rep ; 7(1): 15522, 2017 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-29138416

RESUMO

Plants actively respond to herbivory by inducing various defense mechanisms in both damaged (locally) and non-damaged tissues (systemically). In addition, it is currently widely accepted that plant-to-plant communication allows specific neighbors to be warned of likely incoming stress (defense priming). Systemin is a plant peptide hormone promoting the systemic response to herbivory in tomato. This 18-aa peptide is also able to induce the release of bioactive Volatile Organic Compounds, thus also promoting the interaction between the tomato and the third trophic level (e.g. predators and parasitoids of insect pests). In this work, using a combination of gene expression (RNA-Seq and qRT-PCR), behavioral and chemical approaches, we demonstrate that systemin triggers metabolic changes of the plant that are capable of inducing a primed state in neighboring unchallenged plants. At the molecular level, the primed state is mainly associated with an elevated transcription of pattern -recognition receptors, signaling enzymes and transcription factors. Compared to naïve plants, systemin-primed plants were significantly more resistant to herbivorous pests, more attractive to parasitoids and showed an increased response to wounding. Small peptides are nowadays considered fundamental signaling molecules in many plant processes and this work extends the range of downstream effects of this class of molecules to intraspecific plant-to-plant communication.


Assuntos
Comunicação Autócrina/genética , Regulação da Expressão Gênica de Plantas/imunologia , Lycopersicon esculentum/metabolismo , Peptídeos/genética , Imunidade Vegetal/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Sequência de Aminoácidos , Animais , Comunicação Autócrina/imunologia , Ontologia Genética , Herbivoria/fisiologia , Larva/fisiologia , Lycopersicon esculentum/genética , Lycopersicon esculentum/imunologia , Lycopersicon esculentum/parasitologia , Anotação de Sequência Molecular , Peptídeos/síntese química , Peptídeos/imunologia , Folhas de Planta/genética , Folhas de Planta/imunologia , Folhas de Planta/parasitologia , Proteínas de Plantas/classificação , Proteínas de Plantas/imunologia , Receptores de Reconhecimento de Padrão/genética , Transdução de Sinais , Spodoptera/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/imunologia , Transcrição Genética , Compostos Orgânicos Voláteis/imunologia , Compostos Orgânicos Voláteis/metabolismo
13.
Insect Sci ; 24(6): 1025-1033, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28475289

RESUMO

Many fungal root symbionts of the genus Trichoderma are well-known for their beneficial effects on agronomic performance and protection against plant pathogens; moreover, they may enhance protection from insect pests, by triggering plant resistance mechanisms. Defense barriers against insects are induced by the activation of metabolic pathways involved in the production of defense-related plant compounds, either directly active against herbivore insects, or exerting an indirect effect, by increasing the attraction of herbivore natural enemies. In a model system composed of the tomato plant, the aphid Macrosiphum euphorbiae and the parasitoid Aphidius ervi, plant metabolic changes induced by Trichoderma harzianum and their effects on higher trophic levels have been assessed. T. harzianum T22 treatments induce a primed state that upon aphid attacks leads to an increased attraction of aphid parasitoids, mediated by the enhanced production of volatile organic compounds (VOCs) that are known to induce Aphidius ervi flight. Transcriptome sequencing of T22-treated plants infested by aphids showed a remarkable upregulation of genes involved in terpenoids biosynthesis and salicylic acid pathway, which are consistent with the observed flight response of A. ervi and the VOC bouquet profile underlying this behavioral response.


Assuntos
Afídeos/fisiologia , Lycopersicon esculentum/microbiologia , Trichoderma/fisiologia , Compostos Orgânicos Voláteis , Vespas/fisiologia , Animais , Afídeos/parasitologia , Feminino , Voo Animal , Herbivoria , Interações Hospedeiro-Parasita , Lycopersicon esculentum/genética , Simbiose
14.
Insect Sci ; 24(6): 947-960, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28374534

RESUMO

Soil microbial mutualists of plants, including mycorrhizal fungi, non-mycorrhizal fungi and plant growth promoting rhizobacteria, have been typically characterized for increasing nutrient acquisition and plant growth. More recently, soil microbes have also been shown to increase direct plant defense against above- and belowground herbivores. Plants, however, do not only rely on direct defenses when attacked, but they can also recruit pest antagonists such as predators and parasitoids, both above and belowground, mainly via the release of volatile organic compounds (i.e., indirect defenses). In this review, we illustrate the main features and effects of soil microbial mutualists of plants on plant indirect defenses and discuss possible applications within the framework of sustainable crop protection against root- and shoot-feeding arthropod pests. We indicate the main knowledge gaps and the future challenges to be addressed in the study and application of these multifaceted interactions.


Assuntos
Herbivoria , Insetos , Raízes de Plantas/microbiologia , Microbiologia do Solo , Simbiose , Animais , Produtos Agrícolas , Controle Biológico de Vetores
15.
Plant Signal Behav ; 11(7): e1197468, 2016 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-27359066

RESUMO

A multidisciplinary approach, involving eco-physiological, morphometric, biochemical and molecular analyses, has been used to study the impact of two different AM fungi, i.e. Funneliformis mosseae and Rhizophagus intraradices, on tomato response to water stress. Overall, results show that AM symbiosis positively affects the tolerance to drought in tomato with a different plant response depending on the involved AM fungal species.


Assuntos
Secas , Lycopersicon esculentum/microbiologia , Lycopersicon esculentum/fisiologia , Simbiose/fisiologia , Ácido Abscísico/metabolismo , Regulação da Expressão Gênica de Plantas , Glomeromycota/fisiologia , Lycopersicon esculentum/metabolismo , Micorrizas/fisiologia , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Raízes de Plantas/fisiologia
16.
PLoS One ; 11(6): e0157965, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27362639

RESUMO

Pseudococcus comstocki (Hemiptera: Pseudococcidae) is a mealybug species native to Eastern Asia and present as an invasive pest in northern Italy and southern France since the start of the century. It infests apple and pear trees, grapevines and some ornamental trees. Biocontrol programmes against this pest proved successful in central Asia and North America in the second half of the 20th century. In this study, we investigated possible biocontrol agents against P. comstocki, with the aim of developing a biocontrol programme in France. We carried out systematic DNA-barcoding at each step in the search for a specialist parasitoid. First we characterised the French target populations of P. comstocki. We then identified the parasitoids attacking P. comstocki in France. Finally, we searched for foreign mealybug populations identified a priori as P. comstocki and surveyed their hymenopteran parasitoids. Three mealybug species (P. comstocki, P. viburni and P. cryptus) were identified during the survey, together with at least 16 different parasitoid taxa. We selected candidate biological control agent populations for use against P. comstocki in France, from the species Allotropa burrelli (Hymenoptera: Platygastridae) and Acerophagus malinus (Hymenoptera: Encyrtidae). The coupling of molecular and morphological characterisation for both pests and natural enemies facilitated the programme development and the rejection of unsuitable or generalist parasitoids.


Assuntos
Hemípteros/parasitologia , Controle de Insetos/métodos , Parasitos/classificação , Controle Biológico de Vetores/métodos , Animais , Agentes de Controle Biológico , Código de Barras de DNA Taxonômico , França , Interações Hospedeiro-Parasita , Parasitos/isolamento & purificação , Parasitos/fisiologia , Filogenia , Controle da População
17.
Plant Physiol ; 171(2): 1009-23, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27208301

RESUMO

Arbuscular mycorrhizal (AM) fungi, which form symbioses with the roots of the most important crop species, are usually considered biofertilizers, whose exploitation could represent a promising avenue for the development in the future of a more sustainable next-generation agriculture. The best understood function in symbiosis is an improvement in plant mineral nutrient acquisition, as exchange for carbon compounds derived from the photosynthetic process: this can enhance host growth and tolerance to environmental stresses, such as water stress (WS). However, physiological and molecular mechanisms occurring in arbuscular mycorrhiza-colonized plants and directly involved in the mitigation of WS effects need to be further investigated. The main goal of this work is to verify the potential impact of AM symbiosis on the plant response to WS To this aim, the effect of two AM fungi (Funneliformis mosseae and Rhizophagus intraradices) on tomato (Solanum lycopersicum) under the WS condition was studied. A combined approach, involving ecophysiological, morphometric, biochemical, and molecular analyses, has been used to highlight the mechanisms involved in plant response to WS during AM symbiosis. Gene expression analyses focused on a set of target genes putatively involved in the plant response to drought, and in parallel, we considered the expression changes induced by the imposed stress on a group of fungal genes playing a key role in the water-transport process. Taken together, the results show that AM symbiosis positively affects the tolerance to WS in tomato, with a different plant response depending on the AM fungi species involved.


Assuntos
Glomeromycota/fisiologia , Lycopersicon esculentum/microbiologia , Micorrizas/fisiologia , Simbiose , Água/fisiologia , Desidratação , Lycopersicon esculentum/fisiologia , Raízes de Plantas/microbiologia , Raízes de Plantas/fisiologia , Estresse Fisiológico
18.
PLoS One ; 11(2): e0147382, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26840953

RESUMO

Drosophila suzukii (Matsumura), commonly known as Spotted Wing Drosophila (SWD), is a worldwide serious economic threat to the production of berries and stone fruits. The chemical control widely used against this pest is often not able to preventing yield losses because wild flora offers an abundance of fruits to D. suzukii where the pest is able to reproduce and from where it recolonizes neighbouring cultivated fields. Alternatively, within Integrated Pest Management protocols for D. suzukii, biological control could play a key role by reducing its populations particularly in non-cultivated habitats, thus increasing the effectiveness and reducing the side negative effects of other management strategies. Because of the scarcity and of the low efficiency of autochthonous parasitoids in the new invaded territories, in the last few years, a number of surveys started in the native area of D. suzukii to find parasitoid species to be evaluated in quarantine structures and eventually released in the field, following a classical biological control approach. This paper reports the results of these surveys carried out in South Korea and for the first time in China. Among the parasitoids collected, those belonging to the genus Asobara Foerster resulted dominant both by number and species diversity. By combining morphological characters and the mitochondrial COI gene as a molecular marker, we identified seven species of Asobara, of which two associated with D. suzukii, namely A. japonica and A leveri, and five new to science, namely Asobara brevicauda, A. elongata, A mesocauda, A unicolorata, A. triangulata. Our findings offer new opportunity to find effective parasitoids to be introduced in classical biological control programmes in the territories recently invaded by D. suzukii.


Assuntos
Agentes de Controle Biológico , Drosophila/classificação , Himenópteros/classificação , Controle de Insetos/métodos , Comportamento Predatório/fisiologia , Animais , Biodiversidade , China , Produtos Agrícolas , Drosophila/genética , Cadeia Alimentar , Himenópteros/genética , Filogenia
19.
PLoS One ; 10(6): e0128685, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26047349

RESUMO

Delottococcus aberiae De Lotto (Hemiptera: Pseudococcidae) is a mealybug of Southern African origin that has recently been introduced into Eastern Spain. It causes severe distortions on young citrus fruits and represents a growing threat to Mediterranean citrus production. So far, biological control has proven unsatisfactory due to the absence of efficient natural enemies in Spain. Hence, the management of this pest currently relies only on chemical control. The introduction of natural enemies of D. aberiae from the native area of the pest represents a sustainable and economically viable alternative to reduce the risks linked to pesticide applications. Since biological control of mealybugs has been traditionally challenged by taxonomic misidentification, an intensive survey of Delottococcus spp. and their associated parasitoids in South Africa was required as a first step towards a classical biological control programme. Combining morphological and molecular characterization (integrative taxonomy) a total of nine mealybug species were identified in this study, including three species of Delottococcus. Different populations of D. aberiae were found on wild olive trees, in citrus orchards and on plants of Chrysanthemoides monilifera, showing intra-specific divergences according to their host plants. Interestingly, the invasive mealybug populations from Spanish orchards clustered together with the population on citrus from Limpopo Province (South Africa), sharing COI haplotypes. This result pointed to an optimum location to collect natural enemies against the invasive mealybug. A total of 14 parasitoid species were recovered from Delottococcus spp. and identified to genus and species level, by integrating morphological and molecular data. A parasitoid belonging to the genus Anagyrus, collected from D. aberiae in citrus orchards in Limpopo, is proposed here as a good biological control agent to be introduced into Spain.


Assuntos
Hemípteros/parasitologia , Controle Biológico de Vetores , Animais , Teorema de Bayes , Citrus/parasitologia , Haplótipos , Hemípteros/classificação , Hemípteros/genética , Interações Hospedeiro-Parasita , Himenópteros/fisiologia , Filogenia , Especificidade da Espécie
20.
J Plant Physiol ; 173: 28-32, 2015 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-25462075

RESUMO

In the last decade plant-to-plant communication has received an increasing attention, particularly for the role of Volatile Organic Compounds as possible elicitors of plant defense. The role of ß-ocimene as an interspecific elicitor of plant defense has been recently assessed in multitrophic systems including different plant species (Solanaceae, Poaceae, legumes) and different pest species including chewer insects and phytophagous mites. Both chewer insects and phytophagous mites are known to elicit specific plant defensive pathways which are different (at least in part) from those elicited by sap feeders. The aim of this research was to fill this gap of knowledge and to assess the role of ß-ocimene as an elicitor of plant defense against aphid pests, which are sap feeders. For this purpose we used as transgenic tobacco plant releasing an odour plume enriched in this compound as emitter and a tomato plant as receiver. We selected the aphid Macrosiphum euphorbiae and its natural enemy, the parasitoid Aphidius ervi, as the targets of plant induced defense. Tomato plant defense induced by ß-ocimene was assessed by characterizing the aphid performance in terms of fixing behaviour, development and reproduction (direct plant defense) and the parasitoid performance in terms of attraction towards tomato plants (indirect plant defense). The characterization of tomato response to ß-ocimene was completed by the identification of Volatile Organic Compounds as released by conditioned tomato plants. Tomato plants that were exposed to the volatiles of transgenic tobacco enriched in ß-ocimene resulted in less suitable for the aphids in respect to control ones (direct defense). On tomato plants "elicited" by ß-ocimene we recorded: a significant lower number of aphids settled; a significant lower number newborn nymphs; a significant lower weight of aphids feeding. In addition, tomato plants "elicited" by ß-ocimene resulted became more attractive towards the parasitoid A. ervi than control ones. These results could be explained at least in part by examining the composition of the Volatile Organic Compounds released by tomato plants "elicited" by ß-ocimene. Indeed, we found a significantly higher release of several compounds including methyl salicylate and cis-3-hexen-1-ol. These two compounds have been demonstrated to impair aphid development and reproduction and to be involved in the attraction of the aphid parasitoid A. ervi. By considering the ubiquity of ß-ocimene and its ability to regulate the communication of plants belonging 30 to different species (if not families), we concluded that this compound is an ideal candidate for new 31 strategies of sustainable control of agricultural pests.


Assuntos
Alcenos/metabolismo , Afídeos/fisiologia , Interações Hospedeiro-Parasita , Lycopersicon esculentum/imunologia , Imunidade Vegetal , Tabaco/química , Monoterpenos Acíclicos , Animais , Expressão Gênica , Hexanóis/metabolismo , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/genética , Plantas Geneticamente Modificadas , Salicilatos/metabolismo , Tabaco/genética , Compostos Orgânicos Voláteis/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...