Extração de nemátodes de quisto de amostras de solo: método de decantação e crivagem de Cobb vs. método de Fenwick

Potato cyst nematodes are a threat to several agricultural crops around the world with some species considered quarantine pests and subjected to strict regulatory measures in many countries. Usually, cysts nematodes co-exist in the soil with other species of plant-parasitic nematodes, so, a time and cost-efficient extraction technique becomes of primary importance. The ideal extraction method should be able to obtain cysts as well as detecting the presence of other motile plant-parasitic nematodes with a potential impact on potato farming (such as Meloidogyne sp. and Pratylenchus sp.). In recent years, studies have been carried out to test the efficiency of various methods of nematode extraction but few results have been published. Therefore, to test if a method that extracts simultaneously cysts and motile nematodes can be used instead of the reference method that extracts cysts only, the efficiency of Cobb’s decanting and sieving technique was compared to Fenwick’s technique. As a result, in the 74 samples evaluated, a greater number of cysts were extracted from 24 samples using Fenwick’s method and from 11 samples employing Cobb’s decanting and sieving technique. The statistics results showed a significance level of 0,05 using Fenwick’s can allowing to conclude that this method is much more efficient than Cobb’s decanting and sieving technique, and confirming it should not be replaced by alternative methods for cysts extractioninfo:eu-repo/semantics/publishedVersio

Genetic variation in susceptibility to pine wilt disease of maritime pine (Pinus pinaster Aiton) half-sib families

International audienceAbstractKey messageThis paper presents a greenhouse study for assessing the genetic variation in maritime pine (Pinus pinasterAiton) in response to pinewood nematode (Bursaphelenchus xylophilus(Steiner et Buhren) Nickle), which is a causal agent of pine wilt disease. Fifteen out of 96 half-sib families were selected as less susceptible. This experiment is an important first step for creating a resistance breeding program.ContextPine wilt disease is caused by the pinewood nematode (Bursaphelenchus xylophilus (Steiner et Buhren) Nickle), a quarantine pest, and is a concern to maritime pine (Pinus pinaster) in Portugal due to its economic, environmental, and social impacts. This disease is regarded as a major threat to European forests.AimsThis paper aimed to evaluate the genetic variation in maritime pine families that were inoculated with pinewood nematode, identify the most resistant families, and establish the guidelines for a resistance improvement program.MethodsTwo-year-old half-sib progenies obtained from 96 plus trees were inoculated. The plants were monitored for survival on four different dates. The statistical analysis followed the mixed model theory.ResultsGenetic variability of the susceptibility to pine wilt disease was observed. At 157 days after inoculation, the 15 highest genetic ranking families out of 96 were selected, having a predicted survival mean of 15.6% instead of 11.0% on average for the all 96 families.ConclusionThis study allows for the implementation of an improvement program to help control pine wilt disease

species identification, distribution, and new host records in Portugal

Funding Information: This research was supported by the “Fundação para a Ciência e a Tecnologia” (FCT, Portugal) and the European Social Funds, through the “Programa Operacional Regional Centro”, under the Ph.D. fellowship 2020.05541.BD and through the R&D Unit, UIDB/04551/2020 (GREEN-IT—Bioresources for Sustainability). Acknowledgments Funding Information: This research was supported by the “Fundação para a Ciência e a Tecnologia” (FCT, Portugal) and the European Social Funds, through the “Programa Operacional Regional Centro”, under the Ph.D. fellowship 2020.05541.BD and through the R&D Unit, UIDB/04551/2020 (GREEN-IT—Bioresources for Sustainability). Publisher Copyright: Copyright © 2023 Rusinque, Camacho, Serra, Nóbrega and Inácio.Considered one of the most devastating plant parasitic nematodes worldwide, Meloidogyne spp. (commonly known as the root-knot nematodes (RKNs)) are obligate sedentary endoparasites that establish in the roots, causing hyperplasia and hypertrophy of surrounding cells, triggering the formation of galls. These galls will affect root development and physiology, leading to substantial yield losses. During 2017–2022, an extensive survey of Meloidogyne species was undertaken in Portugal (mainland and islands). A total of 1,071 samples were collected by the National Plant Protection Organization (DGAV) and private farmers from different regions of the country and were analysed at the Laboratory of Nematology (NemaINIAV). Samples in which the presence of Meloidogyne sp. was detected were used to perform bioassays to obtain females and juveniles for further studies. Since the accurate identification of RKNs is an important aspect of crop management, morphological and biochemical characterisation was performed. The most common morphological features were observed, showing consistency with previous descriptions of the genus. The biochemical identification using the esterase (EST) phenotype revealed the phenotypes of Meloidogyne arenaria, M enterolobi, M. hispanica, M. hapla, M. incognita, M javanica, and M. luci. Meloidogyne incognita and M. javanica were found to be the most prevalent species in the different regions followed by M. arenaria and M. hapla. This is the first distribution report performed in Portugal on RKNs, contributing to the development of management strategies and to updated information on the status of these pests in Europe.publishersversionpublishe

Teaching methodologies in civil engineering: a multidisciplinary approach

Nowadays universities are rethinking their teaching methodologies not only in order to adapt to the use of new technologies, such as the ICT (information and communication technologies) or the GIS (Geographic Information Systems) but also in order to advance the international students towards a multidisciplinary approach. Thus, this article is the result of a multidisciplinary approach gathering scholars from Portugal and Romania, presenting a set of several teaching methodologies used on the domains of civil engineering. It is based on the experience of the University of Beira Interior (UBI) in Portugal and the Faculty of Constructions, Cadastre and Architecture of the University of Oradea (UO) in Romania. Among other descriptions, the conclusions show that there are several different and common aspects in between the Portuguese and the Romanian experiences. Regarding the common aspects there is the need of finding new teaching methodologies in order to consider the different backgrounds of the international students coming from several countries and continents, having diverse high educational systems. Thus, the international students are encouraged to work together and to actively participate in the development, presentation and discussion of their scientific findings.info:eu-repo/semantics/publishedVersio

Plant-nematode co-cultures in the screening of sustainable nematicides against soil-dwelling parasitic nematodes of plants

The diseases caused by plant parasitic nematodes are still a serious constraint to modern global crop production. An increasing number of active compounds in commercial nematicidal formulations is being banned from use by common policies of pest management. Farmer communities report a low efficiency for the replacement pesticides, which reflects on crop yield and productivity. Novel sustainable biopesticides are urgently needed to cope with global food demands while respecting the most recent environmental policies. Plant-nematode co-cultures offer a stable biotechnological screening tool able to assess the active compound’s nematicidal activity and its effect on host tissues, simultaneously, in an easily accessible system that simulates natural infection. These systems are being developed and optimized at the Nematology laboratory of INIAV. Preliminary results were obtained for co-cultures of Solanum lycopersicum with the nematode Meloidogyne ethiopica and S. tuberosum with Globodera pallida. Future studies will target other plant parasitic nematodes, e.g., the root lesion nematodes (Pratylenchus penetrans) in transgenic roots of potato and the pinewood nematode (Bursaphelenchus xylophilus) on in vitro pine shoots (Pinus sp.)

Linking nematode communities and soil health under climate change

Soil health is intimately intertwined with ecosystem services. Climate change negatively impacts ecosystem functioning, by altering carbon and nitrogen biogeochemical cycles and shifting nutrient bioavailability, thus hampering food production and exacerbating biodiversity loss. Soil ecosystem services are provided by belowground biota, and as the most abundant metazoans on Earth, nematodes are key elements of soil food webs and reliable bioindicators of soil health. Here, we carry out a literature review from 2019, the year that the Intergovernmental Panel on Climate Change published a report relating and expressing serious concerns on the effects of climate change on the land degradation and sustainability of terrestrial ecosystems. We focus on documenting and discussing the composition of nematode communities contributing to improving soil health, and soil management practices to promote their presence and limit the effects of climate change on soils. By recognizing beneficial nematodes as plant-promoting agents, we could harness their potential to our benefit, catalyze decomposition services, improve plant performance, and increase carbon sequestration. This way, we will contribute to soil health and a well-balanced and well-managed system, making it possible to increase productivity, guarantee food security, and reduce the yield gap, with a limited human footprint on the environment.D.P. is supported by the Portuguese Foundation for Science and Technology (Fundação para a Ciência e a Tecnologia, FCT/MCTES), through grant 2021.08030.BD. At CBMA, this work was supported by the “Contrato-Programa” UIDB/04050/2020 funded by national funds through the FCT I.P

Six First Reports of Pin Nematodes from Portugal, with an Update of the Systematics, Genetic Diversity, and Phylogeny of the Genus Paratylenchus (Nematoda: Tylenchulidae)

Pin nematodes (Paratylenchus spp.) currently comprise 132 species of polyphagous plant ectoparasites with at least seven species that are plant pathogenic emphasizing the need for correct identification to establish an appropriate management strategy. Sequences of highly conserved regions of ribosomal and mitochondrial RNA genes are a powerful species-level diagnostic tool within Tylenchulidae. A nematological survey was conducted from 2019 to 2021 in commercial vineyards distributed in four major wine-producing regions in the Central and South Portugal. Nine populations of Paratylenchus spp. were isolated from the rhizosphere of grapevines that were characterized from morphological data and molecular phylogenetic analysis using two rRNA genes (D2–D3 expansion segments of the 28S, and partial 18S) and a region partial of the COI mtRNA gene. Contrasting morphological hypotheses with molecular data provided rapid detection of six species, specifically P. goodeyi, P. hamatus, P. pedrami, P. tenicaudatus, P. variabilis, and P. veruculatus. Bayesian inference (BI) phylogenetic trees for these molecular markers established phylogenetic relationships underscore the importance of using genomic and molecular phylogenetic data for accurate pin nematode identification at the species level. To our knowledge, this is the first report of Paratylenchus spp. in Portugal, extending the geographical distribution of these species in the Mediterranean Basin, and the first record of P. goodeyi, P. pedrami, P. variabilis, P. veruculatus and P. tenicaudatus parasitizing grapevine

Bioactivity of Monoterpene Alcohols as an Indicator of Biopesticidal Essential Oils against the Root Knot Nematode Meloidogyne ethiopica

The application of pesticides remains one of the most efficient control methods for phytophagous parasites in crops. Essential oils (EOs) are complex mixtures of highly active compounds that can be used as biopesticides against plant parasitic nematodes. In the present work, the antinematodal activity of the monoterpene alcohols geraniol, linalool, menthol or  -terpineol, which are generally found in high amounts in EOs of some aromatic and medicinal plants, was analyzed on the root knot nematode Meloidogyne ethiopica. Geraniol showed intense and lasting antinematodal activity, suggesting that EOs rich in this compound can be used in the development of nematicidal biopesticides to integrate sustainable pest management strategies against this pest

Insights into the role of fungi in Pine Wilt Disease

Pine wilt disease (PWD) is a complex disease that severely affects the biodiversity and economy of Eurasian coniferous forests. Three factors are described as the main elements of the disease: the pinewood nematode (PWN) Bursaphelenchus xylophilus, the insect‐vector Monochamus spp., and the host tree, mainly Pinus spp. Nonetheless, other microbial interactors have also been considered. The study of mycoflora in PWD dates back the late seventies. Culturomic studies have revealed diverse fungal communities associated with all PWD key players, composed frequently of saprophytic fungi (i.e., Aspergillus, Fusarium, Trichoderma) but also of necrotrophic pathogens associated with bark beetles, such as ophiostomatoid or blue‐stain fungi. In particular, the ophiostomatoid fungi often recovered from wilted pine trees or insect pupal chambers/tunnels, are considered crucial for nematode multiplication and distribution in the host tree. Naturally occurring mycoflora, reported as possible biocontrol agents of the nematode, are also discussed in this review. This review discloses the contrasting effects of fungal communities in PWD and highlights promising fungal species as sources of PWD biocontrol in the framework of sustainable pest management actions

Performance assessment of polymer based electrodes for in vitro electrophysiological sensing: the role of the electrode impedance

Conducting polymer electrodes based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) are used to record extracellular signals from autonomous cardiac contractile cells and glioma cell cultures. The performance of these conducting polymer electrodes is compared with Au electrodes. A small-signal impedance analysis shows that in the presence of an electrolyte, both Au and polymer electrodes establish high capacitive double-layers. However, the polymer/electrolyte interfacial resistance is 3 orders of magnitude lower than the resistance of the metal/electrolyte interface. The polymer low interfacial resistance minimizes the intrinsic thermal noise and increases the system sensitivity. However, when measurements are carried out in current mode a low interfacial resistance partially acts as a short circuit of the interfacial capacitance, this affects the signal shape