Evidence for a cryptic parasitoid species reveals its suitability as a biological control agent.

Uncertainty about the taxonomic status and the specificity of a species commonly prevent its consideration as a candidate for biological control of pest organisms. Here we use a combination of molecular analysis and crossing experiments to gather evidence that the parasitoid wasp Ganaspis brasiliensis, a candidate for biological control of the invasive spotted wing drosophila Drosophila suzukii, is a complex of at least two cryptic species. Complementary experiments demonstrate that individuals from one genetic group readily parasitize several drosophila species regardless of their food source while individuals from the other one are almost exclusively specific to larvae feeding in ripening fruits. Because only D. suzukii attacks ripening fruits in its area of invasion, parasitoids from this second group appear to be well suited as a biological control agent. Our study demonstrates the need for a combination of biosystematics with biological and ecological investigations for the development of safe and efficient biological control programs

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Study of the overwintering ecology of the hazelnut pest, Palomena prasina (Hemiptera: Pentatomidae) in a perspective of Integrated Pest Management

<p class="MsoNormal"><em>Palomena prasina</em>, the green shield bug (GSB), is widely distributed in the Eurosiberian region. In the Southwest of France it is considered a serious pest of hazelnuts, its feeding punctures lead to blank hazelnuts and kernel necrosis, causing heavy losses in commercial orchards. To date, no Integrated Pest Management strategy is available to control <em>P. prasina</em>.</p> <p class="MsoNormal">Control strategies often focus on the pests' spring-summer ecology, when they are in the field or in the vicinity of crops. However, the abundance of pest populations in crops is also related to their autumn-winter ecology.  The present work focussed on the autumn-winter ecology of <em>P. prasina</em> to identify new opportunities for this pest suppression. We investigate (i) where <em>P. prasina</em> overwinters, (ii) if it aggregates in its overwintering sites, and (iii) if it mates while overwintering. Samples were collected over a two-year period in different ecosystems (forests, hedges, orchards), in human-made structures, and habitats (litter, bushes/trees, dead trees). The reproductive status of GBS individuals was monitored in winter, and in spring when they emerged from overwintering sites.</p> <p class="MsoNormal">Our results show that 97% <em>P. prasina</em> adults overwinter  in the leaf litter of orchards and natural ecosystems and that 70% overwinter individually. The abundance of GSB in those sites is negatively correlated with litter temperature and positively correlated with humidity levels. Furthermore, adults only mate after leaving their overwintering site. Finally, there was an important number of overwintering adults hosting endoparasitoids (32%).</p> <p class="MsoNormal">The fact that GSB overwinters alone in the leaf litter means controlling its populations by destroying the overwintering sites is not a solution. All the same, our results do open new perspectives for the control of <em>P. prasina</em>. First, the emergence traps, in particular the cone traps, proved efficient for collecting emerging adults and could be used for monitoring. Moreover, our observations point out the existence of long-range mating signals that could be exploited for trapping. Last but not least, the important number of overwintering parasitised adults is a promising biocontrol avenue.</p><p>Funding provided by: European Community*<br>Crossref Funder Registry ID: <br>Award Number: </p><p>Funding provided by: Unicoque*<br>Crossref Funder Registry ID: <br>Award Number: </p><p>Funding provided by: Association Nationale des Producteurs de Noisettes*<br>Crossref Funder Registry ID: <br>Award Number: </p><div><em>Material and methods</em></div> <div><em>1. Characterisation of overwintering sites</em></div> <div> </div> <div>A field study was conducted in a zone with a radius of 20 km around the city of Cancon, France (44°32'09.7"N, 0°37'30.1"E, 160 m a.s.l.) from December to February (10 weeks), both in 2021 and 2022.</div> <div> </div> <div>In 2021, three different types of ecosystems were studied: hazelnut orchards, linear hedges and woods. The hazelnut orchards were over 20 years old, at least 1 ha in size, and most of them were planted with the Pauetet cultivar, which is sensitive to<em> P. prasina</em>. They were all commercial orchards with no cultural practices or pesticide spraying during the study period (the last management practices before that period correspond to pesticide spraying in July and harvest in August-September). The linear hedges were lines of trees and bushes that separated two fields, and were more than 116 m in length. The woods were at least 0.68 ha in size. The hedges and the woods were mainly composed of local deciduous trees, different species of oak, chestnut, hornbeam, checker tree, and some shrubs including dogwood and hawthorn; evergreen bushes included wild blackberry, butcher's broom, and wild madder ( Bonneaud, 2014; Badeau et al., 2017). In 2022, apple orchards were added to the above-mentioned ecosystems. The apple orchards were at least 3.36 ha in size. All the orchards were managed conventionally and most were surrounded by crops, mainly hazelnut, plum, and apple orchards. Ten sites representing each ecosystem, located at least 8 km apart, were selected for the study. Each week, one site of each ecosystem type was prospected (i.e. each site was prospected only once per year).</div> <div> </div> <div>Three main types of habitat were sampled in each ecosystem: leaf litter, the bark of trees and the foliage of evergreen bushes. Five samples were collected at 10-m intervals along a 50 m transect in the hedges and at the edges of orchards and woods starting at 0 m and continuing to 40 m. A further 5 samples were collected at the centre of the orchards and woods, at a distance of between 10 and 50 m from the edge.</div> <div> </div> <div>A total of 600 leaf litter samples were collected, of 1 m2 each (250 and 350 samples were collected in 2021 and 2022 respectively). For each sample, four abiotic parameters were recorded at the surface of the litter using a TR-74Ui Series data logger (TandD corporation, Japan): temperature, relative humidity, illuminance and UV. The depth of the leaf litter was also measured. After the measurements were complete, the leaf litter covering each 1 m2 area was collected separately, placed in a black plastic bag and transported to the laboratory. The contents of each bag were placed under a photo-eclector trap (Soil photo-eclector Ø1m2, ecoTech Umwelt-Meßsysteme GmbH, Germany) for 24 h at 25 °C under constant light (Philips Master TDL 18W/840 Cool white), after which the presence of insects was checked in each trap. At the end of the 24-h period, the photo-eclector traps were removed, and leaf litter was carefully inspected for any remaining insects.</div> <div> </div> <div>We then defined an area with a radius of 2 metres around each leaf litter sampling area. In this area, the bark of one dead or standing tree was inspected visually for 2 minutes, and one evergreen bush was prospected for 10 seconds using a beating tray.</div> <div> </div> <div>Finally, during the same monitoring period, a survey was conducted of potential overwintering sites in human-made structures (buildings and houses) based on a call for witnesses broadcast by radio, on Internet, and using flyers. Witnesses were asked to take photos of stink bugs present in their houses and buildings and to send them to the laboratory by email together with information on the general geographical location, plus the exact place and date of collection. Thirty-seven volunteers in the Cancon region responded to the call.</div> <div> </div> <div>All the individuals belonging to the Pentatomoidea collected in the above-mentioned samples were identified to species level.</div> <div> </div> <div>The abundance of <em>P. prasina</em> in the 600 leaf litter samples was analysed. We fitted a Generalised Linear Mixed Model (GLMM) with a Poisson error distribution and the following fixed effects: type of ecosystem (categorial factors: hedge, woods, apple and hazelnut orchards), zone (categorial factors: interface and centre; interface corresponds to samples collected in the hedges and edges of woods and orchards), abiotic parameters of the leaf litter (continuous factors: litter depth, temperature, humidity, light and UV), study year (categorial factors: 2021 and 2022). To consider the spatial autocorrelation, we added the sampling site as a random effect.</div> <div> </div> <div>The goodness of fit was evaluated through the randomised quantile residuals calculated using the DHARMa package (version 0.4.6; (Hartig, 2022). The GLMM was performed with the HLfit function of the spaMM package (version 3.13.0; Rousset and Ferdy, 2014) using R software version: 4.1.2.; (Development Core Team, 2021). P-values were calculated using the type II log likelihood ratio test (hereafter L.R.). We started with a model including all the double interactions between the zone and the other seven independent variables and removed them when they were not significant. This first model is called "Full model".</div> <div> </div> <div>The same statistical procedure was applied to two partial models focused on <em>P. prasina</em> abundance in the 250 samples collected in the centre of woods and orchards (called the "Centre model") and in the 350 samples collected at the edge of woods and orchards and in the hedges (called the "Interface model"). The effect "zone" was removed from each of those GLMM and the remaining fixed and random effects were tested. Using the two final partial models and the "predict" function in R, we calculated the predicted number of <em>P. prasina</em> individuals. We computed predictions and their 95% confidence intervals according to each type of ecosystem and for the year in which the largest number of individuals was recorded, except the apple orchard ecosystem which was only sampled in 2022. Furthermore, the quantitative predictive variables with no significant effect were set to their average value and the random effect was not included in the calculation.</div> <div> </div> <div>Next, a qualitative variable with two categories corresponding to high and low values of the parameter was created for the quantitative abiotic parameters which showed a significant effect in the partial models. The threshold for defining these categories was determined by selecting a value that minimised the P-value of the effect associated with this new qualitative variable in the partial model. In simple terms, this threshold represents a value above which the number of <em>P. prasina</em> individuals in our leaf litter samples changed significantly.</div> <div> </div> <div><em>2. Reproductive status</em></div> <div> </div> <div>The reproductive status of <em>P. prasina </em>was assessed for the overwintering adults collected in the leaf litter, as described in the previous section, plus adults emerging from overwintering sites at the end of the hibernation period, captured as described below. The study was performed in 2021-2022.</div> <div> </div> <div>From the end of February to the end of April 2022, adults of <em>P. prasina</em> newly emerged from overwintering sites were collected in two ecosystems: a  2.3 ha hazelnut orchard surrounded by lakes and other hazelnut orchards, located near the village of Moulinet (44°31'23.9"N, 0°36'00.5"E, 117 m a.s.l.), and a 2.25 ha wood surrounded by buildings, crop fields, and hazelnut orchards, located close to the city of Cancon (44°32'34.6"N, 0°35'34.2"E, 97 m a.s.l.). As no information was available concerning the most efficient traps to catch P. prasina emerging from overwintering sites, we used two different kinds of traps. The first was a homemade cone trap (Raney, 1969) adapted from a pop-up mosquito transparent net tent measuring 1.8 m x 2 m x 1.5 m (LxWxH, ®GLKEBY). The adaptation consisted of cutting off the floor of each tent and placing a plastic cone collector, with a1.5 cm Ø entrance at the top of the tent. The tent was kept in place by a 1.50 m wooden pole inserted into the ground at the centre of the tent. The second trap was a homemade trap based on the Circle trap design (Mulder, Reid, Stafne & Grantham, 2012), modified and adapted for P. prasina by enlarging the opening at the top of the trap top from Ø 0.80 cm to 1.50 cm, and by reducing the width of the trap from 81 cm to 66 cm so it fitted the circumference of the tree trunks better.</div> <div> </div> <div>Ten cone traps and 20 Circle traps were installed at each site. The cone traps were spaced about 20 m apart and the Circle traps were fixed to trees growing about 10 m apart. The presence of <em>P. prasina</em> in the traps was checked three times every day: in the morning (at 9 am, at noon, and at 5 pm), to avoid leaving emerging individuals together which could bias the evaluation of mating status (see below).</div> <div> </div> <div>We checked the sexual maturity of both male and female <em>P. prasina </em>collected weekly in the overwintering sites between December and February, in 2020-21 and 2021-22, and in the cone and Circle traps between the end of February and the end of April 2022. All parasitised individuals were excluded from the analyses, as they could interfere with reproductive status (De Salles, 1992). First, we observed the colour of the individuals, which is considered as a proxy for reproductive status in the close species Nezara viridula (L.) and Plautia stali Scott (Musolin & Numata, 2003; Kotaki & Yagi, 1989): russet or reddish brown during the winter reproductive diapause and green during the period of active reproduction. The insects were then killed by freezing at -20 °C for 2 min, dissected and the sexual organs extracted in distilled water under a stereo microscope (Nikon, SMZ1270). Ovarian development was assessed using a scale starting at 0 (previtellogenic females) and going up to 4 (post-reproductive females) (Kiritani, 1963; Nielsen et al., 2017). The mated status of females was evaluated by the presence of spermatozoids in the spermatheca (Golec and Hu, 2015; Hamidi et al., 2021) observed under the microscope. In males, sexual maturity was assessed through the presence of living (i.e. moving) spermatozoids in the testes.</div&gt

Plaagbestrijding met omnivore roofwantsen : effecten van omnivore roofwantsen op plagen in gerbera, tomaat en roos en de risico’s op bloem- en vruchtschade

Omnivore roofwantsen van de familie Miridae hebben de bijzondere eigenschap dat ze zowel van plantmateriaal als van prooien kunnen leven. Dit brede voedselmenu heeft enorme voordelen voor de biologische bestrijding, omdat ze daardoor verschillende plaagsoorten kunnen bestrijden en tegelijkertijd preventief ingezet kunnen worden doordat ze zich voeden met plantsappen en/of alternatief voedsel. Dit voordeel van plantenvoeding is tegelijkertijd een nadeel, omdat de wantsen ook schade kunnen geven aan bloemen en vruchten. In dit project is de potentie voor plaagbestrijding met een aantal soorten omnivore roofwantsen onderzocht in gerbera, roos en tomaat. De plaagbestrijding was gericht op wittevlieg (gerbera en tomaat), Echinothrips (roos en gerbera), Tuta absoluta (tomaat), Turkse mot (gerbera en tomaat) en Nesidiocoris tenuis (tomaat). Daarnaast hebben we gekeken naar de schade die ze kunnen veroorzaken in gerbera en tomaat en is gekeken naar methoden om vestiging te verbeteren.---Omnivorous predators of the Miridae family feed both on plant and prey. This ability is a huge advantage forestablishment into crops when pests are absent or scarce, but at the same time a risk when through plantfeeding fruit and flowers get damaged. In this project we evaluated the potential for pest control with miridpredators in gerbera, rose and tomato crops. Pest control was assessed for whiteflies (gerbera and tomato),Echinothrips (gerbera and rose), Tuta absoluta (tomato), The Tomato Looper (gerbera and tomato) andNesidiocoris tenuis (tomato). In gerbera and tomato, not only pest control, but also the level of crop damagethese mirids can cause was assessed. Finally, methods to enhance establishment were evaluated

Regulatory T Cell Responses to High-Dose Methylprednisolone in Active Systemic Lupus Erythematosus.

A slight increase in the proportion of circulating regulatory T (Treg) cells has been reported in systemic lupus erythematosus (SLE) patients taking oral prednisone. The effects of intravenous (IV) high dose methylprednisolone (MP) on Tregs have not yet been described, especially in active SLE.We prospectively analyzed the proportion of circulating CD4+ Treg cell subsets defined as follows: (1) naïve Treg (nTreg) FoxP3lowCD45RA+ cells; (2) effector Treg (eTreg) FoxP3highCD45RA- cells; and (3) non-suppressive FoxP3lowCD45RA- cells (non-regulatory Foxp3low T cells). Peripheral blood mononuclear cells of patients with active SLE were analyzed before the first infusion of IV high dose MP (day 0) and the following days (day 1, day 2, ±day 3 and ±day 8). The activity of SLE was assessed by the SLEDAI score.Seventeen patients were included. Following MP infusions, the median (range) percentage of eTregs significantly increased from 1.62% (0.53-8.43) at day 0 to 2.80% (0.83-14.60) at day 1 (p = 0.003 versus day 0), 4.64% (0.50-12.40) at day 2 (p = 0.06 versus day 1) and 7.50% (1.02-20.70) at day 3 (p = 0.008 versus day 2), and declined to baseline values at day 8. Expanding eTreg cells were actively proliferating, as they expressed Ki-67. The frequency of non-regulatory FoxP3low T cells decreased from 6.39% (3.20-17.70) at day 0 to 4.74% (1.03-9.72) at day 2 (p = 0.005); nTreg frequency did not change. All patients clinically improved immediately after MP pulses. The absence of flare after one year of follow up was associated with a higher frequency of eTregs at day 2.IV high dose MP induces a rapid, dramatic and transient increase in circulating regulatory T cells. This increase may participate in the preventive effect of MP on subsequent flares in SLE

Combination of IL-2, rapamycin, DNA methyltransferase and histone deacetylase inhibitors for the expansion of human regulatory T cells

International audienceFOXP3+ regulatory T cell (Treg) based cellular therapies represent promising therapeutic options in autoimmunity, allergy, transplantation and prevention of Graft Versus Host (GVH) Disease. Among human FOXP3-expressing CD4+T cells, only the CD45RA+ naïve Treg (nTreg) subset is suitable for in vitro expansion. However, FoxP3 expression decays in cells using currently described culture protocols. Rapamycin alone was not able to prevent FOXP3 loss in nTregs cells, as only a half of them maintained FOXP3 expression after 14 days of culture. In contrast we report a novel combined drug regimen that can drastically stabilize FOXP3 expression in cultured Tregs. IL-2, rapamycin, histone deacetylase and DNA methyltransferase inhibitors act in synergy to allow expansion of human regulatory T cells with sustained high expression of FOXP3 and CD15s with potent suppressive capacities in vitro and control of murine xeno-GVH reactions. Of note, an additional subsequent infusion of expanded nTreg cells did not improve survival of mice. Combination of IL-2, rapamycin, histone deacetylase and DNA methyltransferase inhibitors is optimal for the expansion in vitro of pure effective nTreg maintaining high levels of FOXP3 for therapeutic purposes

Frequencies of eTreg cells in SLE patients according to their clinical response following IV methylprednisolone pulses.

<p><b>(A)</b> Evolution of the SELENA-SLEDAI score at baseline, month 3, 6 and 12 following IV MP pulses according to the responder status of the patients defined after 12 months of follow-up. <b>(B)</b> Effector Treg frequencies at day 0 (baseline) and day 2 and the ratio of effector Tregs between day 2 and day 0 in poor and good responders after 12 months of follow-up. (A-B) Each dot represents an individual and lines show median values. Statistical analyses were performed using the Wilcoxon matched pairs signed ranks test (A) and the Mann-Whitney <i>U</i> test (B).</p

Cytofluorometric analysis of CD4⁺FoxP3⁺ T cell subsets following IV methylprednisolone pulses in SLE patients.

<p>Fresh PBMCs from SLE patients were analyzed by flow cytofluorometry, gated on CD4⁺ T lymphocytes, for the expression of FoxP3 and CD45RA (top rows) and Ki-67 (bottom rows). FoxP3⁺CD4⁺ T cells can be divided into CD4⁺CD45RA⁻FoxP3^bright effector Tregs (eTregs) and CD4⁺CD45RA⁺FoxP3⁺ naïve Tregs (nTregs), while the remaining CD4⁺CD45RA⁻FoxP3^low include a notable amount of non-regulatory, cytokine-secreting, activated T cells (non-regulatory FoxP3⁺ T cells) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143689#pone.0143689.ref008" target="_blank">8</a>]. FoxP3^highKi-67⁺ (right gate), which correspond to the eTregs, and FoxP3⁻Ki-67⁺ (left gate), which correspond to non-regulatory T-cells, are shown on the lower FACS panel. Percentages of the different subsets are shown. Representative analyses from one SLE patient are shown (pt #3).</p

Frequencies of CD4⁺FoxP3⁺ T cell subsets following IV methylprednisolone pulses in SLE patients.

<p>Fresh PBMCs from SLE patients were analyzed by flow cytofluorometry as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143689#pone.0143689.g001" target="_blank">Fig 1</a>. Kinetics of <b>(A)</b> effector Tregs, <b>(B)</b> naïve Tregs and <b>(C)</b> non-regulatory FoxP3⁺ T cells were performed in patients with active SLE undergoing IV high dose MP pulse treatment at baseline. Seventeen patients at baseline and day 2, 8 patients at day 3 and 6 patients at day 8 were assessed. (A) Right panel, eTreg cells frequencies at day 3 are displayed (except for two patients for whom these data are missing; eTreg cells frequencies at day 2 are shown instead). Each dot represents an individual assessed in an independent experiment, and the grey bar shows median values. Statistical analyses were performed using the Wilcoxon matched pairs signed ranks test.</p

Baseline characteristics and disease parameters of the SLE patients^*.

<p>* except where indicated otherwise, values are the number (%) of patients. SLE = Systemic Lupus Erythematosus; SELENA-SLEDAI = Safety of Estrogens in Lupus Erythematosus National Assessment (SELENA) version of the SLE Disease Activity Index (SLEDAI).</p><p>^† Excluding antimalarial and prednisone.</p><p>Baseline characteristics and disease parameters of the SLE patients^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0143689#t001fn001" target="_blank">*</a>}.</p