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Abbasi B.H.,Quaid-i-Azam University | Anjum S.,Quaid-i-Azam University | Hano C.,CNRS Laboratory of Woody Plants and Crops Biology
RSC Advances | Year: 2017

The use of plants and plant-derived materials for biosynthesis of zinc oxide nanoparticles (ZnO NPs) is developing into a lucrative field of green nanotechnology and gaining more importance owing to its simplicity, rapidity, and eco-friendliness. In present study, a novel and efficient green approach has been developed for biosynthesis of ZnO NPs by exploiting the in vitro platform of plants. Two different in vitro cultures extracts i.e.; callus extract (CE) and adventitious root extract (RE) of Flax were used as a source of reducing and stabilizing agents. Phytochemical analysis revealed that the RE was rich in phytochemical reducing agents as compared to CE. UV-visible spectroscopy showed that the bioreduction of RE-mediated ZnO NPs completed in shorter time than CE-mediated ZnO NPs. Scanning electron microscopy showed that CE-mediated ZnO NPs were spherical with weak agglomeration but the RE-mediated ZnO NPs were hexagonal in shape with uniform distribution of particles. X-ray diffraction analysis showed that the both type of ZnO NPs exhibited the same crystalline nature (wurtzite hexagonal) but vary in their sizes. RE-mediated ZnO NPs were smaller in size (34.97 nm) than CE-mediated ZnO NPs (61.44 nm). Fourier-transform infrared spectroscopy revealed that the polyphenols (lignans), carboxylic acids and aromatic compounds were mainly involved in reduction and capping of both type of ZnO NPs. Moreover, the RE-mediated ZnO NPs showed more potent antibacterial and antileishmanial activity against multidrug resistant bacterial strains and parasite of Leishmania major than CE-mediated ZnO NPs. The present work highlighted the potent role of in vitro cultures of Flax in enhanced biosynthesis, antibacterial and antileishmanial activities of ZnO NPs. © The Royal Society of Chemistry.

Fichot R.,CNRS Laboratory of Woody Plants and Crops Biology | Brignolas F.,CNRS Laboratory of Woody Plants and Crops Biology | Cochard H.,French National Institute for Agricultural Research | Cochard H.,University Blaise Pascal | Ceulemans R.,University of Antwerp
Plant, Cell and Environment | Year: 2015

Vulnerability to drought-induced cavitation is a key trait of plant water relations. Here, we summarize the available literature on vulnerability to drought-induced cavitation in poplars (Populus spp.), a genus of agronomic, ecological and scientific importance. Vulnerability curves and vulnerability parameters (including the water potential inducing 50% loss in hydraulic conductivity, P50) were collected from 37 studies published between 1991 and 2014, covering a range of 10 species and 12 interspecific hybrid crosses. Results of our meta-analysis confirm that poplars are among the most vulnerable woody species to drought-induced cavitation (mean P50=-1.44 and -1.55MPa across pure species and hybrids, respectively). Yet, significant variation occurs among species (P50 range: 1.43MPa) and among hybrid crosses (P50 range: 1.12MPa), within species and hybrid crosses (max. P50 range reported: 0.8MPa) as well as in response to environmental factors including nitrogen fertilization, irradiance, temperature and drought (max. P50 range reported: 0.75MPa). Potential implications and gaps in knowledge are discussed in the context of poplar cultivation, species adaptation and climate modifications. We suggest that poplars represent a valuable model for studies on drought-induced cavitation, especially to elucidate the genetic and molecular basis of cavitation resistance in Angiosperms. Over the last 25 years our knowledge with regard to the anatomical, physiological and ecological aspects of vulnerability to cavitation has grown considerably. It is now clear that vulnerability to drought-induced cavitation is a key trait of plant water-relations. As poplars (Populus spp.) are among the fastest growing temperate hardwood trees and high water consumers, they are particularly sensitive to water limitations and to drought induced cavitation. The Populus genus has therefore been studied quite intensively. In our review contribution we review and synthesize all the data published in the literature since 1991 on drought induced cavitation in poplar. We discuss and analyse the literature data in terms of (i) genetic variations among and within pure species or hybrids, and (ii) acclimation in response to environmental factors (drought, nutrients, light...). We also link the observations from this comprehensive review with other anatomical and ecophysiological traits. Practical implications, actual gaps in knowledge and future research opportunities offered by poplar as a model tree are also presented. © 2014 John Wiley & Sons Ltd.

Hulle M.,French National Institute for Agricultural Research | Coeur d'Acier A.,French National Institute for Agricultural Research | Bankhead-Dronnet S.,CNRS Laboratory of Woody Plants and Crops Biology | Harrington R.,Rothamsted Research
Comptes Rendus - Biologies | Year: 2010

Global warming is one of the principal challenges facing insects worldwide. It affects individual species and interactions between species directly through effects on their physiology and indirectly through effects on their habitat. Aphids are particularly sensitive to temperature changes due to certain specific biological features of this group. Effects on individuals have repercussions for aphid diversity and population dynamics. At a pan- European scale, the EXAMINE observation network has provided evidence for an increase in the number of aphid species present over the last 30 years and for earlier spring flights. We review these results and provide a review of the principal effects of global warming on aphid communities. © 2010 Académie des sciences.

Deguines N.,CNRS Science Conservation Center | Jono C.,CNRS Science Conservation Center | Baude M.,University of Bristol | Baude M.,CNRS Laboratory of Woody Plants and Crops Biology | And 3 more authors.
Frontiers in Ecology and the Environment | Year: 2014

Unprecedented growth in human populations has required the intensification of agriculture to enhance crop productivity, but this was achieved at a major cost to biodiversity. There is abundant local-scale evidence that both pollinator diversity and pollination services decrease with increasing agricultural intensification. This raises concerns regarding food security, as two-thirds of the world's major food crops are pollinator-dependent. Whether such local findings scale up and affect crop production over larger scales is still being debated. Here, we analyzed a country-wide dataset of the 54 major crops in France produced over the past two decades and found that benefits of agricultural intensification decrease with increasing pollinator dependence, to the extent that intensification failed to increase the yield of pollinator-dependent crops and decreased the stability of their yield over time. This indicates that benefits from agricultural intensification may be offset by reductions in pollination services, and supports the need for an ecological intensification of agriculture through optimization of ecosystem services. © The Ecological Society of America.

Mannai S.,CNRS Laboratory of Woody Plants and Crops Biology | Bitri L.,University of Tunis | Thany S.H.,CNRS Laboratory of Woody Plants and Crops Biology
Journal of Neurochemistry | Year: 2016

Insect neurosecretory cells, called dorsal unpaired median neurons, are known to express two α-bungarotoxin-insensitive nicotinic acetylcholine receptor (nAChR) subtypes, nAChR1 and nAChR2. It was demonstrated that nAChR1 was sensitive to cAMP/cAMP-dependent protein kinase (PKA) regulation, resulting in a modulation of nicotine currents. In this study, we show that cyclic guanosine monophosphate (cGMP)/cGMP-dependent protein kinase (PKG) pathway modulates nicotine-induced currents, as increased cGMP affects the second compound of the biphasic current-voltage curve, corresponding to the nAChR2 receptors. Indeed, maintaining the guanosine triphosphate level with 100 μM guanosine triphosphate-γ-S increased nicotine currents through nAChR2. We also demonstrated that inhibition of PKG activity with 0.2 μM (8R,9S,11S)-(-)-9-methoxy-carbamyl-8-methyl-2,3,9,10-tetrahydro-8,11-epoxy-1H,8H,11H-2,7b,11a-trizadibenzo-(a,g)-cycloocta-(c,d,e)-trinden-1-one (KT5823), a PKG specific inhibitor, reduced nicotine-induced current amplitudes. KT5823 effect on nicotine currents is associated with calcium (Ca2+) activity because inhibition of Ca2+ concentration with cadmium chloride (CdCl2) abolished KT5823-induced inhibition mediated by nAChR2. However, specific inhibition of nitric oxide-guanylyl cyclase (GC) complex by 10 μM 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) significantly increased nicotine-induced current amplitudes on both nAChR1 and nAChR2. These results suggest that nicotine-induced currents mediated by both α-bungarotoxin-insensitive nAChR1 and nAChR2 are coupled to the cGMP/PKG pathway. © 2016 International Society for Neurochemistry.

Perdereau E.,CNRS Research Institute of Insect Biology | Bagneres A.-G.,CNRS Research Institute of Insect Biology | Bankhead-Dronnet S.,CNRS Laboratory of Woody Plants and Crops Biology | Dupont S.,CNRS Research Institute of Insect Biology | And 3 more authors.
Molecular Ecology | Year: 2013

Biological invasions are recognized as a major threat to both natural and managed ecosystems. Phylogeographic and population genetic analyses can provide information about the geographical origins and patterns of introduction and explain the causes and mechanisms by which introduced species have become successful invaders. Reticulitermes flavipes is a North American subterranean termite that has been introduced into several areas, including France where introduced populations have become invasive. To identify likely source populations in the USA and to compare the genetic diversity of both native and introduced populations, an extensive molecular genetic study was undertaken using the COII region of mtDNA and 15 microsatellite loci. Our results showed that native northern US populations appeared well differentiated from those of the southern part of the US range. Phylogenetic analysis of both mitochondrial and nuclear markers showed that French populations probably originated from southeastern US populations, and more specifically from Louisiana. All of the mtDNA haplotypes shared between the United States and France were found in Louisiana. Compared to native populations in Louisiana, French populations show lower genetic diversity at both mtDNA and microsatellite markers. These findings are discussed along with the invasion routes of R. flavipes as well as the possible mechanisms by which French populations have evolved after their introduction. © 2012 Blackwell Publishing Ltd.

Vala J.-C.,CNRS Laboratory of Woody Plants and Crops Biology | Williams C.D.,National University of Ireland, Maynooth
Zoosystema | Year: 2015

Only six species of Sciomyzidae Fallén, 1820, with 106 individuals, have been identified from Malaise traps installed during the ATBI at sites near 1400 and 2000 m in the Mercantour National Park, France. They belong to the subfamilies Phaeomyiinae Steyskal, 1965, represented by Pelidnoptera nigripennis (Fabricius, 1794) and the Sciomyzinae Schiner, 1862 for the other five species. The species are essentially characteristic of open, dry or wet meadows and forest macrohabitats. Pelidnoptera nigripennis larvae are parasitoids of millipedes, while the others are parasitoids or predators of terrestrial snails and slugs. The list given here includes three species (one Tetanocerini and two Sciomyzini Cresson, 1920) already reported from the National Park, where we captured eight specimens of one of them, subsequent to the ATBI period of study. Dichetophora finlandica Verbeke, 1964 is cited for the first time in the Park. The altitudinal distribution of the species is discussed. © Publications scientifiques du Muséum national d'Histoire naturelle, Paris.

Horn A.,CNRS Laboratory of Woody Plants and Crops Biology | Kerdelhue C.,Montpellier SupAgro | Lieutier F.,CNRS Laboratory of Woody Plants and Crops Biology | Rossi J.-P.,Montpellier SupAgro
Agricultural and Forest Entomology | Year: 2012

1 Various factors such as climate and resource availability influence the geographical distributions of organisms. Species sensitive to small temperature variations are known to experience rapid distribution shifts as a result of current global warming, sometimes leading to new threats to agriculture and forests. Tomicus piniperda and Tomicus destruens (Coleoptera, Curculionidae, Scolytinae) cause economic damage to pines in Europe and around the Mediterranean Basin. However, their respective potential distributions have not yet been studied at a large scale. The present study aimed to investigate the influence of climatic and host factors on the geographical distributions of both Tomicus species in Europe and around the Mediterranean Sea, and to establish maps of suitable areas. 2 Using 114 published localities where the presence or absence of both species was unambiguously recorded, we gathered WorldClim meteorological records to correlate the occurrence of insects with bioclimatic variables and to build potential distribution maps. 3 The two studied Tomicus species presented parapatric distributions and opposite climate demands, with T. destruens occurring in locations with warmer temperatures, whereas T. piniperda occurs under a colder climate. Amongst the investigated climate variables, temperature appeared to be most correlated with both species distributions. 4 The potential ranges of both species were further restricted by the availability of pine hosts. It appeared that setting new pine plantations in regions where T. destruens or T. piniperda are still absent could favour a rapid expansion of their distributions. Our data will be useful when aiming to apply management strategies adapted to each species, and to forecast their potential range expansions/contractions as a result of climate warming. 2012 The Royal Entomological Society.

Taillebois E.,French Institute of Health and Medical Research | Thany S.H.,CNRS Laboratory of Woody Plants and Crops Biology
Insects | Year: 2016

The modes of action of most insecticides are known, but little information exists regarding the toxicological interactions involving insecticide mixtures at low doses. The effects of mixtures of four insecticides were investigated using LC10 values (concentration leading to 10% mortality), acetamiprid (ACE, 0.235 µg/mL), chlorpyriphos (CHL, 107.0 µg/mL), deltamethrin (DEL, 5.831 µg/mL), and fipronil (FIP, 3.775 µg/mL) on the larvae of the pea aphid, Acyrthosiphon pisum. After 24 h exposure, 6 of the 11 tested combinations, DEL/FIP, ACE/DEL, CHL/FIP, ACE/DEL/FIP, ACE/CHL/FIP, and ACE/DEL/CHL/FIP, were toxic through an additive effect. Four combinations, ACE/FIP, DEL/CHL, ACE/CHL, and ACE/DEL/CHL had a synergistic effect, whereas only one DEL/CHL/FIP showed an antagonistic effect. The toxic effect of these mixtures was confirmed after 48 h of exposure, revealing an enhanced toxicity of CHL, DEL, and FIP in combination with ACE. We suggest that an insect pest management strategy should be evaluated in the future using different combinations of insecticides. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

Salle A.,CNRS Laboratory of Woody Plants and Crops Biology | Nageleisen L.-M.,Ministere de lAgriculture | Lieutier F.,CNRS Laboratory of Woody Plants and Crops Biology
Forest Ecology and Management | Year: 2014

Oak declines are multifactorial processes in which bark and wood boring (BWB) beetles can act as major inciting factors, killing the weakened trees. Nonetheless, the current knowledge on the biology, ecology of these species is scattered and no efficient management strategies are currently available. Based on the existing literature and field observations from the French forest health service, we firstly identified the prominent BWB species implicated in oak declines in Europe. Secondly we performed a state of the art on the biology and ecology of these species, with a particular reference to the interactions with their host trees. Finally considerations were made on how climate change could affect these interactions. Six species, namely Agrilus biguttatus, Coraebus florentinus, Coraebus undatus, Cerambyx cerdo, Platypus cylindrus and Scolytus intricatus are frequently implicated in oak declines in Europe. The interactions with their hosts regarding selection and resistance are generally poorly known. Likewise, these beetles are associated with a diverse microbial community, which composition and implication in the biology of insects and decline processes is unclear in most cases. Climate change will probably increase the frequency and distribution of oak declines in Europe. It will also likely modify the interactions between oaks and these beetles by promoting contributing factors of decline, modifying directly and indirectly host resistance, phenology and attractiveness, and beetles development, distribution and interaction with microorganisms. Evidences point out that the increase in temperature has already favored the distribution and development of C. florentinus and could enhance the development of other species. Potential research prospects are proposed, aiming at acquiring missing basic knowledge and improving the currently limited management strategies. © 2014 Elsevier B.V.

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