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Survival and growth of woody species in the Mediterranean are mainly restricted by water availability. We tested the hypothesis that Mediterranean species acclimate their xylem vulnerability and osmotic potential along a precipitation gradient.We studied five predominant co-occurring Mediterranean species; Quercus calliprinos, Pistacia palaestina, Pistacia lentiscus, Rhamnus lycioides and Phillyrea latifolia, over two summers at three sites. The driest of the sites is the distribution edge for all the five species. We measured key hydraulic and osmotic traits related to drought resistance, including resistance to embolism (psi(50)) and the seasonal dynamics of water and osmotic potentials.The leaf water potentials (psi(l)) of all species declined significantly along the summer, reaching significantly lower psi(l) at the end of summer in the drier sites. Surprisingly, we did not find plasticity along the drought gradient in psi(50) or osmotic potentials. This resulted in much narrower hydraulic safety margins (HSMs) in the drier sites, where some species experienced significant embolism.Our analysis indicates that reduction in HSM to null values put Mediterranean species in embolism risk as they approach their hydraulic limit near the geographical dry edge of their distribution.

The World Health Organization Global Action Plan recommends integrated surveillance programs as crucial strategies for monitoring antibiotic resistance. Although several national surveillance programs are in place for clinical and veterinary settings, no such schemes exist for monitoring antibiotic-resistant bacteria in the environment. In this transnational study, we developed, validated, and tested a low-cost surveillance and easy to implement approach to evaluate antibiotic resistance in wastewater treatment plants (WWTPs) by targeting cefotaxime-resistant (CTX-R) coliforms as indicators. The rationale for this approach was: i) coliform quantification methods are internationally accepted as indicators of fecal contamination in recreational waters and are therefore routinely applied in analytical labs; ii) CTX-R coliforms are clinically relevant, associated with extended-spectrum β-lactamases (ESBLs), and are rare in pristine environments. We analyzed 57 WWTPs in 22 countries across Europe, Asia, Africa, Australia, and North America. CTX-R coliforms were ubiquitous in raw sewage and their relative abundance varied significantly (

The broad variability of Cucumis melo (melon, Cucurbitaceae) presents a challenge to conventional classification and organization within the species. To shed further light on the infraspecific relationships within C. melo, we compared genotypic and metabolomic similarities among 44 accessions representative of most of the cultivar-groups. Genotyping-by-sequencing (GBS) provided over 20,000 single-nucleotide polymorphisms (SNPs). Metabolomics data of the mature fruit flesh and rind provided over 80,000 metabolomic and elemental features via an orchestra of six complementary metabolomic platforms. These technologies probed polar, semi-polar, and non-polar metabolite fractions as well as a set of mineral elements and included both flavor-and taste-relevant volatile and non-volatile metabolites. Together these results enabled an estimate of “metabolomic/elemental distance” and its correlation with the genetic GBS distance of melon accessions. This study indicates that extensive and non-targeted metabolomics/elemental characterization produced classifications that strongly, but not completely, reflect the current and extensive genetic classification. Certain melon Groups, such as Inodorous, clustered in parallel with the genetic classifications while other genome to metabolome/element associations proved less clear. We suggest that the combined genomic, metabolic, and element data reflect the extensive sexual compatibility among melon accessions and the breeding history that has, for example, targeted metabolic quality traits, such as taste and flavor. Fil: Moing, Annick. Universite de Bordeaux; Francia Fil: William Allwood, J.. The James Hutton Institute; Reino Unido Fil: Aharoni, Asaph. Weizmann Institute Of Science Israel; Israel Fil: Baker, John. Rothamsted Research; Reino Unido Fil: Beale, Michael H.. Rothamsted Research; Reino Unido Fil: Ben-Dor, Shifra. Weizmann Institute Of Science Israel; Israel Fil: Biais, Benoît. Universite de Bordeaux; Francia Fil: Brigante, Federico Iván. Max Planck Institute Of Molecular Plant Physiology; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; Argentina Fil: Burger, Yosef. Agricultural Research Organization Of Israel; Israel Fil: Deborde, Catherine. Universite de Bordeaux; Francia Fil: Erban, Alexander. Max Planck Institute Of Molecular Plant Physiology; Alemania Fil: Faigenboim, Adi. Agricultural Research Organization Of Israel; Israel Fil: Gur, Amit. Agricultural Research Organization Of Israel; Israel Fil: Goodacre, Royston. University of Liverpool; Reino Unido Fil: Hansen, Thomas H.. Universidad de Copenhagen; Dinamarca Fil: Jacob, Daniel. Universite de Bordeaux; Francia Fil: Katzir, Nurit. Agricultural Research Organization Of Israel; Israel Fil: Kopka, Joachim. Max Planck Institute Of Molecular Plant Physiology; Alemania Fil: Lewinsohn, Efraim. Agricultural Research Organization Of Israel; Israel Fil: Maucourt, Mickael. Universite de Bordeaux; Francia Fil: Meir, Sagit. Weizmann Institute Of Science Israel; Israel Fil: Miller, Sonia. Rothamsted Research; Reino Unido Fil: Mumm, Roland. Wageningen University & Países Bajos Fil: Oren, Elad. Agricultural Research Organization Of Israel; Israel Fil: Paris, Harry S.. Agricultural Research Organization Of Israel; Israel Fil: Rogachev, Ilana. Weizmann Institute Of Science Israel; Israel Fil: Rolin, Dominique. Universite de Bordeaux; Francia Fil: Saar, Uzi. Agricultural Research Organization Of Israel; Israel Fil: Schjoerring, Jan K.. Universidad de Copenhagen; Dinamarca Fil: Tadmor, Yaakov. Agricultural Research Organization Of Israel; Israel Fil: Tzuri, Galil. Agricultural Research Organization Of Israel; Israel Fil: de Vos, Ric C. H.. Wageningen University & Países Bajos Fil: Ward, Jane L.. Rothamsted Research; Reino Unido Fil: Yeselson, Elena. Agricultural Research Organization Of Israel; Israel Fil: Hall, Robert D.. Wageningen University & Países Bajos Fil: Schaffer, Arthur A.. Agricultural Research Organization Of Israel; Israel

In Integrated Pest Management programs, insecticides are applied to agricultural crops when pest densities exceed a predetermined economic threshold. Under conditions of high natural enemy density, however, the economic threshold can be increased, allowing for fewer insecticide applications. These adjustments, called ‘dynamic thresholds’, allow farmers to exploit existing biological control interactions without economic loss. Further, the ability of natural enemies to disperse from, and subsequently immigrate into, insecticide-sprayed areas can affect their biological control potential. We develop a theoretical approach to incorporate both pest and natural enemy movement across field borders into dynamic thresholds and explore how these affect insecticide applications and farmer incomes. Our model follows a pest and its specialist natural enemy over one growing season. An insecticide that targets the pest also induces mortality of the natural enemy, both via direct toxicity and reduced resource pest densities. Pest and natural enemy populations recover after spraying through within-field reproduction and by immigration from neighboring unsprayed areas. The number of insecticide applications and per-season farmer revenues are calculated for economic thresholds that are either fixed (ignoring natural enemy densities) or dynamic (incorporating them). The model predicts that using dynamic thresholds always leads to reduced insecticide application. The benefit of dynamic thresholds in reducing insecticide use is highest when natural enemies rapidly recolonize sprayed areas, and when insecticide efficacy is low. We discuss real-life situations in which monitoring of natural enemies would substantially reduce insecticide use and other scenarios where the presence of beneficial organisms may lead to threshold modifications.

The knowledge on symbiotic microorganisms of insects has increased in recent years, yet relatively little data is available on non-pathogenic viruses. Here we studied the virome of the parasitoid wasp Anagyrus vladimiri (Hymenoptera: Encyrtidae), a biocontrol agent of mealybugs. By high-throughput sequencing of viral nucleic acids, we revealed three novel viruses, belonging to the families Reoviridae (provisionally termed AnvRV [Anagyrus vladimiri reovirus]), Iflaviridae (AnvIFV) and Dicistroviridae (AnvDV). Phylogenetic analysis further classified the AnvRV in the genus Idnoreovirus, and the AnvDV in the genus Triatovirus. The genome of AnvRV is comprised of 10 distinct genomic segments ranging in length from 1.5 to 4.2 Kbp, but only two out of the 10 open reading frames (ORFs) have a known function. AnvIFV and AnvDV each have one polypeptide ORF, which is typical to iflaviruses but very un-common among dicistroviruses. AnvRV was found to be fixed in a mass-reared population of A. vladimiri, whereas it’s prevalence in field-collected wasps was ~15%. Similarly, the prevalence of AnvIFV and AnvDV were much higher in the mass rearing population than in the field population. Transmission electron micrographs of females’ ovaries revealed clusters and viroplasms of Reovirus-like particles in follicle cells. AnvRV was not detected in the mealybugs, suggesting that this virus is truly associated with the wasps. The possible effects of these viruses on A. vladimiri’s biology, and on biocontrol agents in general are discussed. Our findings identify RNA viruses as potential players involved in the multitrophic system of mealybugs, their parasitoids and other members of the holobiont.ImportanceDifferent biological control approaches use industrially mass-reared natural enemy insects to reduce damage of arthropod pests. Such mass-reared cultures may be positively and/or negatively affected by various microorganisms, including viruses. Yet, current knowledge on virus diversity, especially in arthropods, is limited. Here, we provide the first virome characterization of a member of the wasps family Encyrtidae - the member being the parasitoid Anagyrus vladimiri - a commercially important natural enemy of mealybug pests. We describe the genome of three previously unknown RNA viruses, co-inhabiting this parasitoid, and elaborate on the prevalence of those viruses in individual wasps of both mass-reared and environmental origins. Microscopy images suggest that at least one of the viruses is transmitted maternally via the ovaries. We discuss the genomic structure of the viruses and the possible relationship between those viruses and the A. vladimiri host, with implications on improvement of biocontrol of mealybug pests.

Made available in DSpace on 2022-04-28T19:40:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-06-01 Pepper cultivation in Israel has been constrained by two sympatric poleroviruses, Pepper vein yellows virus-2 (PeVYV-2) and Pepper whitefly-borne vein yellows virus (PeWBVYV), which are transmitted specifically by aphids and whiteflies, respectively. This study investigated the interaction between PeVYV-2 and PeWBVYV inside the host plant and the insect vectors. Our results show that PeVYV-2 and PeWBVYV compete against each other inside the host plant and also inside aphids. PeWBVYV was the weaker competitor inside the host plant, with diminished transmission rates when inoculated simultaneously or successively after PeVYV-2 and could only be transmitted efficiently when inoculated first and then challenged by PeVYV-2. Successive inoculations of plants with viruliferous whiteflies with PeWBVYV followed by viruliferous aphids with PeVYV-2 led to a coinfection rate of 60%, but with severely reduced titers of PeWBVYV in the coinfected plants compared with singly infected plants. In contrast, PeVYV-2 was the weaker competitor inside the insect vector, with reduced quantities of the acquired virus and a reduced transmission rate by aphids when given prior acquisition on PeWBVYV. However, we also show that the transmission efficiency of PeVYV-2 and PeWBVYV from coinfected plants by whiteflies and aphids remained comparable to that from singly infected plants. This is likely attributable to the reduced titers of PeWBVYV inside coinfected plants causing lesser impact on transmission of PeVYV-2 by aphids and the stronger competitiveness of PeWBVYV inside the whitefly. Competitive interactions between PeVYV-2 and PeWBVYV inside the host plant and insect vector can thus be beneficial for their coexistence. Department of Entomology Volcani Center Faculdade de Ci^encias Agron^omicas São Paulo State University (UNESP) Faculdade de Ci^encias Agron^omicas São Paulo State University (UNESP)

SummaryChromatin is a dynamic platform within which gene expression is controlled by epigenetic modifications, notably targeting amino acid residues of histone H3. Among them is Lysine 27 of H3 (H3K27), which trimethylation by the Polycomb Repressive Complex 2 (PRC2) is instrumental in regulating spatio-temporal patterns of key developmental genes. H3K27 is also subjected to acetylation, found at sites of active transcription. Most information on the function of histone residues and their associated modifications in plants was obtained from studies of loss-of-function mutants for the complexes that modify them.In order to decrypt the genuine function of H3K27, we expressed a non-modifiable variant of H3 at residue K27 (H3.3K27A) in Arabidopsis, and developed a multi-scale approach combining in-depth phenotypical and cytological analyses, with transcriptomics and metabolomics.We uncovered that the H3.3K27A variant causes severe developmental defects, part of them reminiscent of PRC2 mutants, part of them new. They include early flowering, increased callus formation, and short stems with thicker xylem cell layer. This latest phenotype correlates with mis-regulation of phenylpropanoid biosynthesis.Overall, our results reveal novel roles of H3K27 in plant cell fates and metabolic pathways, and highlight an epigenetic control point for elongation and lignin composition of the stem.

International audience; This review summarizes the current understanding of the development of the neuroendocrine gonadotropin-releasing hormone (GnRH) system, including discussion on open questions regarding (1) transcriptional regulation of the Gnrh1 gene; (2) prenatal development of the GnRH1 system in rodents and humans; and (3) paracrine and synaptic communication during migration of the GnRH cells.

22 Pág. Centro de Investigación Forestal (CIFOR), Purpose of Review: Recognizing that in the context of global change, tree genetic diversity represents a crucial resource for future forest adaptation, we review and highlight the major forest genetics research achievements of the past decades in biodiversity-rich countries of the Mediterranean region. For this, we conducted a bibliometric analysis of the scientific literature spanning the past thirty years (1991–2020). Putting together the representative regionwide expertise of our co-authorship, we propose research perspectives for the next decade. Recent Findings: Forest genetics research in Mediterranean countries is organized into three different scientific domains of unequal importance. The domain “Population diversity and Differentiation” related to over 62% of all publications of the period, the domain “Environmental conditions, growth and stress response” to almost 23%, and the domain “Phylogeography” to almost 15%. Citation rate was trending the opposite way, indicating a strong and sustained interest in phylogeography and a rising interest for genetics research related to climate change and drought resistance. The share of publications from Asia and Africa to the total within the Mediterranean increased significantly during the 30-year period analyzed, reaching just below 30% during the last decade. Summary: Describing poorly known species and populations, including marginal populations, using the full potential of genomic methods, testing adaptation in common gardens, and modeling adaptive capacity to build reliable scenarios for forest management remain strategic research priorities. Delineating areas of high and low genetic diversity, for conservation and restoration, respectively, is needed. Joining forces between forest management and forest research, sharing data, experience, and knowledge within and among countries will have to progress significantly, e.g., to assess the potential of Mediterranean genetic resources as assisted migration material worldwide. Introductory quote:: Let us collect with care the facts we can observe, let us consult experience wherever we can, and when this experience is inaccessible to us, let us assemble all the inductions which observation of facts analogous to those which escape us can furnish and let us assert nothing categorically; in this way, we shall be able little by little to discover the causes of a multitude of natural phenomena, and, perhaps, even of phenomena which seem the most incomprehensible.. J.B. de Lamarck (Philosophie zoologique, 1809), cited by O. Langlet (1971)., European Union’s Horizon 2020 research and innovation program under grant agreement No. 676876 COST Action FP1202 “Strengthening conservation: a key issue for adaptation of marginal/peripheral populations of forest trees to climate change in Europe (MaP-FGR)

With a growing number of parasites and pathogens experiencing large-scale range expansions, monitoring diversity in immune genes of host populations has never been so important because it can inform on the adaptive potential to resist the invaders. Population surveys of immune genes are becoming common in many organisms, yet they are missing in the honey bee (Apis mellifera L.), a key managed pollinator species that has been severely affected by biological invasions. To fill the gap, here we identified single nucleotide polymorphisms (SNPs) in a wide range of honey bee immune genes and developed a medium-density assay targeting a subset of these genes. Using a discovery panel of 123 whole-genomes, representing seven A. mellifera subspecies and three evolutionary lineages, 180 immune genes were scanned for SNPs in exons, introns (< 4 bp from exons), 3’ and 5´UTR, and < 1 kb upstream of the transcription start site. After application of multiple filtering criteria and validation, the final medium-density assay combines 91 quality-proved functional SNPs marking 89 innate immune genes and these can be readily typed using the high-sample-throughput iPLEX MassARRAY system. This medium-density-SNP assay was applied to 156 samples from four countries and the admixture analysis clustered the samples according to their lineage and subspecies, suggesting that honey bee ancestry can be delineated from functional variation. In addition to allowing analysis of immunogenetic variation, this newly-developed SNP assay can be used for inferring genetic structure and admixture in the honey bee. We are deeply indebted to Frank Aguiar, Luís Silva, Edgardo Melo, João Martins, João Melo, Manuel Moura, Manuel Viveiros, and Ricardo Sousa from "Direção Regional da Agricultura e Desenvolvimento Rural dos Açores" (Portugal), and to Laura Garreau, Laurent Maugis, Pascale Sauvage and Jacques Kermagoret, from “Association Conservatoire de l’Abeille Noir Bretonne” (France), for sampling the apiaries in São Miguel, Santa Maria, and Ouessant islands. Genotyping was outsourced to the Epigenetics and Genotyping laboratory, Central Unit for Research in Medicine (UCIM), University of Valencia, Spain. Data analyses were performed using computational resources at the Research Centre in Digitalization and Intelligent Robotics (CeDRI), Instituto Politécnico de Bragança. Ana Rita Lopes is supported by a PhD scholarship (SFRH/BD/143627/2019) from the Foundation for Science and Technology (FCT), Portugal. FCT provided financial support by national funds (FCT/MCTES) to CIMO (UIDB/00690/2020).This research was funded through the projects BEEHAPPY (POCI-01-0145- FEDER-029871, FCT and COMPETE/QREN/EU) and BEEHEAL. BEEHEAL was funded by the ARIMNet2 2016 Call by the following agencies: INIA (Spain), MOARD (Israel), ANR (France) and FCT (Portugal). ARIMNet2 (ERA-NET) received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 618127. info:eu-repo/semantics/publishedVersion

International audience; Pectobacterium brasiliense (Pbr) infects a wide range of crops worldwide, causing potato blackleg and soft rot and vegetable soft rots. This study aimed to characterize the genetic diversity and virulence variability among 68 Pbr strains isolated from either symptomless potato progeny tubers, diseased potato plants, ware potatoes wash water, or vegetables grown in Israel, as well as strains isolated from symptomless seed tubers grown in Europe, or diseased potato plants grown in France. The collection was typed using PCR and TaqMan real-time PCR analyses, dnaX sequence analysis, pulsed-field gel electrophoresis (PFGE), and pectolytic activity. dnaX phylogeny grouped almost all strains in a common genetic clade related to Pbr, which was distinct from the other Pectobacterium species. PFGE analysis identified two main clusters, including one major group of 47 strains with 95%-100% similarity. Maceration assays on two potato cultivars showed significant differences between strains but with no correlations with the source of the strains nor the status of the host (with/without symptoms). Molecular (dnaX sequences and PFGE profiles) and phenotypic analyses (tuber maceration tests) showed that the tested Pbr strains are not a homogeneous group. Analysis of the tested Pbr strains isolated from potato and vegetables grown in fields with a history of potato cultivation suggests that seed tubers imported from Europe may be the main source for Pbr in Israel. To the best of our knowledge, this is the first study that describes biodiversity and population structure of P. brasiliense isolated from potato and vegetables under hot climate conditions

International audience; The small ruminant (SR) value chain in Europe is a complex matrix of stakeholders with very different interests and profiles where it is not possible to establish one-size-fits-all solutions. The aim of this paper is to present the TechCarestrategies to manage animal welfare using innovative technologies, that are investigated through a multi-actor approach which takes into account the local SR production systems and involves all relevant stakeholders, from farmers totransporters, slaughterhouse, consumers and regulators. This co-design approach aims to: (1) Identify all relevant actors in SR value chain and train facilitators to engage stakeholders in continuous interaction and feedback to the rest of the project activities; (2) explore attitudes, behavioural dynamics and perceptions of stakeholders and their implications for prioritizing welfare issues and using innovative technologies to manage animal welfare at different production stages, and analyse the sustainability of the identified technologies by exploring their environmental, social, economic and cultural impacts. A series of engagements (i.e. one-on-one interviews, focus groups, questionnaires, nominal grouptechniques, concept mapping, etc.) will be set at regular stages in the project, for consultation and exchange of ideas and thus allowing co-design and co-innovation in a multi-actor approach. Among those, two national workshops peryear are planned in each of the nine partner countries to allow feedback and to effectively design business models and develop training and dissemination activities.

International audience; Knowledge on the use of PLF technologies (Tech) at different levels of the value chain for small ruminants (SR) was updated. Their uses for addressing animal welfare (Care) were analysed with a scientific literature review (SciRev).Keywords (n=67) were identified and SciRev was launched by TechCare partners, using several engines. A total of 991 abstracts were identified. Records entailing both Tech and Care (TC papers) were retained and classifiedaccording to the Tech and targeted Care indicators, animal species, production type and farming system. The outcome was a shared database compiling details of 368 TC for which a corresponding Mendeley PDF database was builtand made available online. Preliminary analyses shows that most frequent Care issues are related to malnutrition (monitored by behavioural sensors), general or chronic fear, transport and heat stress. Image analysis (video camera)is the most quoted Tech, followed by GPS (mainly for animal geo-referencing), accelerometry, heart rate measures and ultrasonography. Many technologies are used to monitor the same Care issue. The range of Tech is narrower foradequate housing, where environmental sensors are often coupled with body thermal condition/emission. There are few Tech for detecting mastitis, lameness and endoparasites. Preliminary results suggest that early warning systemsbased on different interoperating sensors are needed to effectively monitor welfare issues such as malnutrition. Further research is required to match effectively Tech and prioritised Care issues in the context of TechCare project.

International audience; Rural economies across Europe, and associated countries, heavily rely on small ruminant (SR) systems, particularly in areas unsuitable for other agriculture livestock production systems. Despite recent advances in precision livestock farming (PLF) and digital technologies (DT) to facilitate farm management, there is a slow rate of uptake by SR producers. This paper presents the project Sm@RT, which aims to improve the understanding, awareness and uptake of different technologies currently available to the SR sector, and further to facilitate ‘solutions to needs’ and identification of technology gaps. Sm@RT focus is on the use of PLF and DT across all types of sheep and goat management systems and environments, to develop a long-term, self-sustainable European/International network to encouragethe use of PLF and DT across the sectors. Eight countries (UK, Ireland, Norway, Estonia, France, Italy, Hungary, Israel) are involved in Sm@rt. The paper presents the original project’s approach: an interactive transdisciplinary and multi-actor approach relying on well-equipped demonstration farms (‘digifarms’) and innovative commercial farms to foster exchanges within the SR industry. It is an iterative step-by-step approach to engage relevant actors from all stakeholder groups at the appropriate level in the knowledge exchange process, crucial to boost dissemination in a trusting environment. Sm@RT will create opportunities to collect and exchange technical and practical knowledge, with information and guidelines on how to use PLF and DT to gain the best benefits for SR systems of production. This will increase efficiency and sustainability of SR farming systems in Europe and beyond.

There is increasing public concern regarding the fate of antibiotic resistance genes (ARGs) during wastewater treatment, their persistence during the treatment process and their potential impacts on the receiving water bodies. In this study, we used quantitative PCR (qPCR) to determine the abundance of nine ARGs and a class 1 integron associated integrase gene in 16 wastewater treatment plant (WWTP) effluents from ten different European countries. In order to assess the impact on the receiving water bodies, gene abundances in the latter were also analysed. Six out of the nine ARGs analysed were detected in all effluent and river water samples. Among the quantified genes, intI1 and sul1 were the most abundant. Our results demonstrate that European WWTP contribute to the enrichment of the resistome in the receiving water bodies with the particular impact being dependent on the effluent load and local hydrological conditions. The ARGs concentrations in WWTP effluents were found to be inversely correlated to the number of implemented biological treatment steps, indicating a possible option for WWTP management. Furthermore, this study has identified bla(OXA-58) as a possible resistance gene for future studies investigating the impact of WWTPs on their receiving water. (C) 2019 The Authors. Published by Elsevier Ltd. German Federal Ministry of Education and ResearchFederal Ministry of Education & Research (BMBF) [02WU1351A]; project STARE -Stopping Antibiotic Resistance Evolution [WaterJPI/0001/2013]; project HYREKA (BMBF)Federal Ministry of Education & Research (BMBF); Working Group 5: Wastewater Reuse and Contaminants of Emerging Concern from Norman activities; NIVA's Strategic Research Initiative on Emerging Environmental Contaminants (Research Council of Norway) [208430] The study has been funded by the German Federal Ministry of Education and Research [02WU1351A]. CMM, TB, TS, DFK acknowledge the national funding agencies through the project WaterJPI/0001/2013 STARE -Stopping Antibiotic Resistance Evolution and the project HYREKA (BMBF). This work was supported by Working Group 5: Wastewater Reuse and Contaminants of Emerging Concern from Norman activities (http://www.norman-network.net/?q=node/106).CS acknowledges the financial support from NIVA's Strategic Research Initiative on Emerging Environmental Contaminants (Research Council of Norway; contract no. 208430).

Climate change is causing temperature increment in crop production areas worldwide, generating conditions of heat stress that negatively affect crop productivity. Tomato (Solanum lycopersicum), a major vegetable crop, is highly susceptible to conditions of heat stress. When tomato plants are exposed to ambient day/night temperatures that exceed 32 °C/20 °C, respectively, during the reproductive phase, fruit set and fruit weight are reduced, leading to a significant decrease in yield. Processing tomato cultivars are cultivated in open fields, where environmental conditions are not controlled; therefore, plants are exposed to multiple abiotic stresses, including heat stress. Nonetheless, information on stress response in processing tomatoes is very limited. Understanding the physiological response of modern processing tomato cultivars to heat stress may facilitate the development of thermotolerant cultivars. Here, we compared two tomato processing cultivars, H4107 and H9780, that we found to be constantly differing in yield performance. Using field and temperature-controlled greenhouse experiments, we show that the observed difference in yield is attributed to the occurrence of heat stress conditions. In addition, fruit set and seed production were significantly higher in the thermotolerant cultivar H4107, compared with H9780. Despite the general acceptance of pollen viability as a measure of thermotolerance, there was no difference in the percentage of viable pollen between H4107 and H9780 under either of the conditions tested. In addition to observations of similar pollen germination and bud abscission rates, our results suggest that processing tomato cultivars may present a particular case, in which pollen performance is not determining reproductive thermotolerance. Our results also demonstrate the value of combining controlled and uncontrolled experimental settings, in order to validate and identify heat stress-related responses, thus facilitating the development of thermotolerant processing tomato cultivars., Our paper deals with the response of tomato plants to high temperatures. Tomato is an important crop, and tomato plants are very sensitive to high temperatures. Therefore, the increase in temperatures due to climate change poses a threat to tomato production. We found that a specific tomato cultivar is heat stress-tolerant, with better productivity under high temperatures. Usually, such tolerance is linked with pollen grains viability. Interestingly, in our case, pollen characteristics were eliminated as a causal factor for heat stress tolerance, meaning that other factors are involved. Follow-up studies are performed towards the development of heat-tolerant tomato.

Filling large data-gaps in Micro-Meteorological data has mostly been done using interpolation techniques based on a marginal distribution sampling. Those methods work well but need a large horizon of the previous events to achieve good results since they do not model the system but only rely on previously encountered iterations. In this paper, we propose to use multi-head deep attention networks to fill gaps in Micro-Meteorological Data. This methodology couples large-scale information extraction with modeling capabilities that cannot be achieved by interpolation-like techniques. Unlike Bidirectional RNNs, our architecture is not recurrent, it is simple to tune and our data efficiency is higher. We apply our architecture to real-life data and clearly show its applicability in agriculture, furthermore, we show that it could be used to solve related problems such as filling gaps in cyclic-multivariate-time-series.

n the past centuries, viruses have benefited from globalization to spread across the globe, infecting new host species and populations. A growing number of viruses have been documented in the western honey bee, Apis mellifera. Several of these contribute significantly to honey bee colony losses. This review synthetizes the knowledge of the diversity and distribution of honey-bee-infecting viruses, including recent data from high-throughput sequencing (HTS). After presenting the diversity of viruses and their corresponding symptoms, we surveyed the scientific literature for the prevalence of these pathogens across the globe. The geographical distribution shows that the most prevalent viruses (deformed wing virus, sacbrood virus, black queen cell virus and acute paralysis complex) are also the most widely distributed. We discuss the ecological drivers that influence the distribution of these pathogens in worldwide honey bee populations. Besides the natural transmission routes and the resulting temporal dynamics, global trade contributes to their dissemination. As recent evidence shows that these viruses are often multihost pathogens, their spread is a risk for both the beekeeping industry and the pollination services provided by managed and wild pollinators., publishedVersion

Numerous studies have recently reported on the discovery of bee viruses in different arthropod species and their possible transmission routes, vastly increasing our understanding of these viruses and their distribution. Here, we review the current literature on the recent advances in understanding the transmission of viruses, both on the presence of bee viruses in Apis and non-Apis bee species and on the discovery of previously unknown bee viruses. The natural transmission of bee viruses will be discussed among different bee species and other insects. Finally, the research potential of in vivo (host organisms) and in vitro (cell lines) serial passages of bee viruses is discussed, from the perspective of the host-virus landscape changes and potential transmission routes for emerging bee virus infections.

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are widely distributed in the environment where they represent potential public health threats. Quantitative PCR (qPCR) is a suitable approach to detect and quantify ARGs in environmental samples. However, the comparison of gene quantification data between different laboratories is challenging since the data are predominantly obtained under non-harmonized conditions, using different qPCR protocols. This study aimed at carrying out an inter-laboratory calibration in order to assess the variability inherent to the qPCR procedures for quantification of ARGs. With this aim, samples of treated wastewater collected in three different countries were analysed based on common DNA extract pools and identical protocols as well as distinct equipment, reagents batches, and operators. The genes analysed were the 16S rRNA, vanA, blaTEM, qnrS, sul1, blaCTXM-32 and intI1 and the artificial pNORM1 plasmid containing fragments from the seven targeted genes was used as a reference. The 16S rRNA gene was the most abundant, in all the analysed samples, followed by intI1, sul1, qnrS, and blaTEM, while blaCTXM-32 and vanA were below the limit of quantification in most or all the samples. For the genes 16S rRNA, sul1, intI1, blaTEM and qnrS the inter-laboratory variation was below 28% (3-8%, 6-18%, 8-21%, 10-24%, 15-28%, respectively). While it may be difficult to fully harmonize qPCR protocols due to equipment, reagents and operator variations, the inter-laboratory calibration is an adequate and necessary step to increase the reliability of comparative data on ARGs abundance in different environmental compartments and/or geographic regions.

Zucchini yellow mosaic virus (ZYMV; potyviridae) represents a major pathogen of Cucurbitaceae crops. ZYMV resistance in melon PI 414723 is conditioned by a dominant allele at the Zym locus. This resistant accession restricts viral spread and does not develop mosaic symptoms, but necrosis sometimes develops in response to inoculation. In previous studies, Zym has been mapped to linkage group II of the melon genetic map. In the present study, positional cloning of the locus was undertaken, starting from the CM-AG36 SSR marker at approximately 2 cm distance. We utilized five mapping populations that share the same resistant parent, PI 414723, and analyzed a total of 1630 offspring, to construct a high-resolution genetic map of the Zym locus. Two melon BAC libraries were used for chromosome walking and for developing new markers closer to the resistance gene by BAC-end sequencing. A BAC contig was constructed, and we identified a single BAC clone, from the ZYMV susceptible genotype MR-1, that physically encompasses the resistance gene. A second clone was isolated from another susceptible genotype, WMR 29, and the two clones were fully sequenced and annotated. Additional markers derived from the sequenced region delimited the region to 17.6 kb of a sequence that harbors a NAC-like transcription factor and, depending on the genotype, either two or three R-gene homologs with a CC-NBS-LRR structure. Mapping was confirmed by saturating the map with SNP markers using a single mapping population. The same region was amplified and sequenced also in the ZYMV resistant genotype PI 414723. Because numerous polymorphic sites were noted between genotypes, we could not associate resistance with a specific DNA polymorphism; however, this study enables molecular identification of Zym and paves the way to functional studies of this important locus.

International audience; Sugar from nectar or from honeydew can prolong parasitoids’ lifespan, enhance their fecundity and foraging ability, and thereby increase their pest suppression efficiency. Sugar sources within crop monocultures are considered to be limiting for parasitoids. Nevertheless, only few studies have measured the sugar feeding of parasitoid assemblages in agricultural areas or in surrounding non-crop habitats. We used cold anthrone tests to compare the frequency of sugar feeding in parasitoid communities, inside pomegranate orchards and in adjacent natural areas, over two consecutive years. Overall, 40% of the 1610 sampled individuals belonging to 135 species scored positive for sugar. Sugar-feeding frequency was lower within the orchards than in the neighbouring natural areas. The proportion of sugar-fed wasps increased with herbaceous vegetation cover, both within and outside the orchards, suggesting that herbs are a sugar-rich habitat. Parasitoids sampled from trees and from herbs within the orchards had similar frequencies of sugar feeding, despite differences in wasp species composition. Our results probably overestimate sugar-feeding frequencies in the field because sugar-fed individuals have higher longevity and hence are more likely to be sampled. We propose a simple model to approximate this over-sampling bias and apply it to Encarsia inaron (Aphelinidae), one of the most abundant parasitoids in the samples. We conclude that sugar availability potentially limits parasitoid fitness in this agro-ecosystem. This may be due to the low density of plants in natural areas during the Mediterranean summer, and to herbicide applications within the orchards that further suppress non-crop herbs.

BAPGEAPSISUPDATINRA; Productivity of grain crops in semi-arid environments is often affected by drought, which is likely to increase due to predicted climate changes. Wild pea (Pisum fulvum, Pf) accessions sampled across its ecological amplitude in Israel (350-850 mm annual precipitation) were used to assess the genetic diversity for drought responses. We hypothesized that native species evolving under east Mediterranean climate carry adaptive traits to cope with drought stress. Accessions were classified according to SNP variation pattern and habitat ecogeographic parameters. Significant differences were found between the accession groups, but grouping in both systems did not match. Subsequently, 52 Pf accessions and three domesticated pea (Pisum sativum) genotypes were evaluated under well-watered (600mm) and water-limited (300mm) treatments. Total dry matter, grain yield, harvest index and average grain weight were higher in domesticated pea than wild Pf, however several Pf accessions exhibited lower drought susceptibility indices (i.e. greater stability across environments) than domesticated genotypes. Of special interest are a number of Pf genotypes in which low susceptibility to water stress was coupled with relatively high productivity. The sampling habitats of those low susceptibility - high productivity accessions are characterized by mild (400-530mm) annual precipitation. Further sampling and evaluation of Pf from such locations may improve our understanding of pea drought adaptation and yield physiology.

International audience

The number of sensors, ground-based and remote, exploiting the relationship between soil dielectric response and soil water content continues to grow. Empirical expressions for this relationship generally work well in coarse-textured soils but can break down for high-surface area and intricate materials such as clayey soils. Dielectric mixing models are helpful for exploring mechanisms and developing new understanding of the dielectric response in porous media that do not conform to a simple empirical approach, such as clayey soils. Here, we explore the dielectric response of clay minerals and clayey soils using the mixing model approach in the frequency domain. Our modeling focuses on the use of mixing models to explore geometrical effects. New spectroscopic data are presented for clay minerals (talc, kaolinite, illite and montmorillonite) and soils dominated by these clay minerals in the 1 MHz&ndash, 6 GHz bandwidth. We also present a new typology for the way water is held in soils that we hope will act as a framework for furthering discussion on sensor design. We found that the frequency-domain response can be mostly accounted for by adjusting model structural parameters, which needs to be conducted to describe the Maxwell&ndash, Wagner (MW) relaxation effects. The work supports the importance of accounting for soil structural properties to understand and predict soil dielectric response and ultimately to find models that can describe the dielectric&ndash, water content relationship in fine-textured soils measured with sensors.

This is a correction to: Journal of Experimental Botany, Volume 71, Issue 16, 6 August 2020, Pages 4658–4676, https://doi.org/10.1093/jxb/eraa245

Notice à reprendre car pas de clé UT au 19 Septembre; In mammals, leptin and tumor-necrosis factor (TNF) are prominent interacting adipokinesmediating appetite control and insulin sensitivity. While TNF pleiotropically functions in immunedefense and cell survival, leptin is largely confined to signaling energy stores in adipocytes. Knowledgeabout the function of avian leptin and TNF is limited and they are absent or lowly expressed inadipose, respectively. Employing radiation-hybrid mapping and FISH-TSA, we mapped TNF andits syntenic genes to chicken chromosome 16 within the major histocompatibility complex (MHC)region. This mapping position suggests that avian TNF has a role in regulating immune response.To test its possible interaction with leptin within the immune system and beyond, we comparedthe transcription patterns of TNF, leptin and their cognate receptors obtained by meta-analysis ofGenBank RNA-seq data. While expression of leptin and its receptor (LEPR) were detected in thebrain and digestive tract, TNF and its receptor mRNAs were primarily found in viral-infected andLPS-treated leukocytes. We confirmed leptin expression in the duodenum by immunohistochemistrystaining. Altogether, we suggest that whereas leptin and TNF interact as adipokines in mammals,in birds, they have distinct roles. Thus, the interaction between leptin and TNF may be uniqueto mammals.

Melon is an economically important fruit crop that has been cultivated for thousands of years; however, the genetic basis and history of its domestication still remain largely unknown. Here we report a comprehensive map of the genomic variation in melon derived from the resequencing of 1,175 accessions, which represent the global diversity of the species. Our results suggest that three independent domestication events occurred in melon, two in India and one in Africa. We detected two independent sets of domestication sweeps, resulting in diverse characteristics of the two subspecies melo and agrestis during melon breeding. Genome-wide association studies for 16 agronomic traits identified 208 loci significantly associated with fruit mass, quality and morphological characters. This study sheds light on the domestication history of melon and provides a valuable resource for genomics-assisted breeding of this important crop., This work was supported by funding from the Agricultural Science and Technology Innovation Program (to Yongyang Xu, S.H., Z.Z. and H.W.), the China Agriculture Research System (CARS-25 to Yongyang Xu and H.W.), the Leading Talents of Guangdong Province Program (00201515 to S.H.), the Shenzhen Municipal (The Peacock Plan KQTD2016113010482651 to S.H.), the Dapeng district government, National Natural Science Foundation of China (31772304 to Z.Z.), the Science and Technology Program of Guangdong (2018B020202007 to S.H.), the National Natural Science Foundation of China (31530066 to S.H.), the National Key R&D Program of China (2016YFD0101007 to S.H.), USDA National Institute of Food and Agriculture Specialty Crop Research Initiative (2015-51181-24285 to Z.F.), the European Research Council (ERC-SEXYPARTH to A.B.), the Spanish Ministry of Economy and Competitiveness (AGL2015–64625-C2-1-R to J.G.-M.), Severo Ochoa Programme for Centres of Excellence in R&D 2016–2010 (SEV-2015–0533 to J.G.-M.), the CERCA Programme/Generalitat de Catalunya to J.G.-M. and the German Science Foundation (SPP1991 Taxon-OMICS to H.S.).

Made available in DSpace on 2019-10-06T15:57:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-12-01 The Bemisia tabaci is a polyphagous insect and a successful vector of plant viruses. B. tabaci is a species complex and in Brazil native species from the New World (NW) group, as well as the invasive species, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) were reported. For better understanding the distribution of the different species four years after the Mediterranean species invasion in Brazil, whiteflies were collected from 237 locations throughout the country between the years of 2013 and 2017, species were identified and the facultative endosymbionts detected. The survey revealed that MEAM1 was the prevalent species found on major crops across Brazil. It is the only species present in North, Northwestern and Central Brazil and was associated with virus-infected plants. MED was found in five States from Southeast to South regions, infesting mainly ornamental plants and was not associated with virus-infected plants. The prevalent endosymbionts identified in MEAM1 were Hamiltonella and Rickettsia; and the mtCOI analysis revealed low genetic diversity for MEAM1. In contrast, several different endosymbionts were identified in MED including Hamiltonella, Rickettsia, Wolbachia and Arsenophonus; and two distinct genetic groups were found based on the mtCOI analysis. Monitoring the distribution of the whiteflies species in Brazil is essential for proper management of this pest. São Paulo State University UNESP-FCA Department of Plant Protection CEP Corteva Agriscience Instituto Agronômico de Campinas CEP Universidade Federal de Pelotas Department of Plant Protection CEP Santa Catarina State University UDESC Department of Agronomy/Plant Pathology Institute of Plant Protection Department of Entomology The Volcani Center The University of Western Australia ARC Centre of Excellence in Plant Energy Biology and School of Chemistry and Biochemistry Crawley São Paulo State University UNESP-FCA Department of Plant Protection CEP

International audience; FtsZ proteins of the FtsZ1 and FtsZ2 families play important roles in the initiation and progression of plastid division in plants and green algae. Arabidopsis possesses a single FTSZ1 member and two FTSZ2 members, FTSZ2-1 and FTSZ2-2. The contribution of these to chloroplast division and partitioning has been mostly investigated in leaf mesophyll tissues. Here, we assessed the involvement of the three FtsZs in plastid division at earlier stages of chloroplast differentiation. To this end, we studied the effect of the absence of specific FtsZ proteins on plastids in the vegetative shoot apex, where the proplastid-to-chloroplast transition takes place. We found that the relative contribution of the two major leaf FtsZ isoforms, FtsZ1 and FtsZ2-1, to the division process varies with cell lineage and position within the shoot apex. While FtsZ2-1 dominates division in the Ll and L3 layers of the shoot apical meristem (SAM), in the L2 layer, FtsZ1 and FtsZ2-1 contribute equally toward the process. Depletion of the third isoform, FtsZ2-2, generally resulted in stronger effects in the shoot apex than those observed in mature leaves. The implications of these findings, along with additional observations made in this work, to our understanding of the mechanisms and regulation of plastid proliferation in the shoot apex are discussed.

International audience; MicroRNAs are key regulators in the development processes or stress responses in plants. In the last decade, several conserved or non-conserved microRNAs have been identified in Medicago truncatula. Different strategies leading to the inactivation of microRNAs in plants have been described. Here, we propose a protocol for an effective inactivation of microRNAs using a STTM strategy in M. truncatula transgenic roots.

International audience; We have developed a series of synthetic constructs suitable to genetically manipulate a broad range of yeast species belonging to the fungal CTG clade. This molecular toolbox notably allows heterologous gene expression, single or dual fluorescence labeling and construction of luciferase-expressing strains for bioluminescence imaging.

Wood density, considered a heritable trait, is often associated with drought tolerance and can be a useful trait for tree breeders to select drought-tolerant provenances. Provenance trials are a useful tool to disentangle genetic variation from plasticity of adaptive traits among populations within the same species. If wood density is a strongly heritable trait selected by climatic conditions, we hypothesize that its variation in provenance trials should be shaped by the provenance climatic variables. To test our hypothesis we collected wood density data of provenance trials from the literature. We used thirty publications published between 1966 and 2015 including 25 species (13 angiosperms and 12 gymnosperms). At the intraspecific level, eight species showed significant positive correlations between wood density and drought conditions of the provenance, two species showed the opposite trend and the remaining 15 species showed no correlation with the climatic conditions of the provenances. For the 10 species with wood density strongly linked to the climatic conditions of the provenance, such relationship reflects a strong genetic determinism and a theoretical fitness optimum. For the other 15 species, wood density does not seem to be the main selection target of drought. This information is critical in the frame of breeding programs for selecting provenances more adaptable to different climate change scenarios.

WOS: 000419228400002 1 The winter pine processionary moth complex includes some major defoliating insects of Pinus and Cedrus forests in southern Europe and the Mediterranean Basin, where they also cause health problems to humans and animals. 2 The complex includes at least two species that were separated recently based on molecular and morphological evidence: Thaumetopoea pityocampa in the west and Thaumetopoea wilkinsoni in the east of the Mediterranean Basin. 3 Individuals from two populations, selected as representative of Th. pityocampa and Th. wilkinsoni, were used to test whether hybridization is possible under controlled conditions. 4 The hybrid offspring showed intermediate morphological and performance traits, whereas heterosis for pupal weight was detected in one of the hybrid lines. The genetic analysis confirmed the crosses. 5 Both species have large phenological plasticity and may come into contact at the edge of their range, where they could hybridize. 6 Based on the evidence accumulated so far, it is recommended that the current species designations are maintained, although a deeper study of the trait variability is required, especially in the contact zones. EU project PROMOTH [QLK5-CT-2002-00852]; University of Padua Dep. DAFNAE We thank M. Cappucci, P. Paolucci and D. Zovi who were involved in running the crossing experiments. We are indebted to M. P. Zalucki and three anonymous reviewers for their useful comments and suggestions. This work was funded by EU project PROMOTH QLK5-CT-2002-00852 and by the University of Padua Dep. DAFNAE.

Productivity of grain crops in semi-arid areas is often affected by drought, which is likely to increase due to climate changes. A collection of 160 wild pea (Pisum fulvum, Pf) accessions was assembled from across its ecological range in Israel (350-850 mm annual precipitation) and used to assess genetic diversity in this taxon. A range of penology and other morpho-physiological traits was documented. We hypothesized that native species evolving under east Mediterranean climate carry adaptive traits to cope with drought stress. Accessions were classified according to SNP variation and habitat ecogeography. Significant differences were found between accession groups, but grouping in both systems did not match. Fifty-two Pf accessions and 3 domesticated (Pisum sativum) genotypes were evaluated, during two seasons, under well-watered (600mm) and water-limited (350mm) conditions. Total dry matter, grain yield, harvest index and average grain weight were higher in domesticated pea than wild Pf, however several Pf accessions exhibited lower drought susceptibility indices (i.e. greater stability across environments) than domesticated pea. Of special interest were a number of Pf genotypes in which low susceptibility to water stress was coupled with relatively high productivity. Sampling habitats of the low susceptibility - high productivity accessions are not the driest ones but are rather characterized by mild (400-530mm) annual precipitation. Further sampling and evaluation of Pf from such locations may improve our understanding of pea drought adaptation and yield physiology.

BGPI : équipe 2; Turnip yellows virus (TuYV) is a polerovirus (family Luteoviridae) restricted to phloem tissue and obligatorily transmitted by aphids in a circulative and non-propagative mode. This virus infects several plant species of economic importance. The icosahedral viral particles contain a single positive strand RNA genome. In order to track virus movement in plants and to measure the impact of aphids presence on virus distribution in plants, a GFP-tagged virus was engineered (TuYV-GFP). In this construct, the GFP sequence was inserted in a non-structural protein sequence involved, to some extent, in virus movement. The fluorescent signal is expected to label virus replicating cells. The TuYV-GFP sequence was introduced into a binary vector to inoculate several plant species by agro infiltration. TuYV-GFP was able to replicate and to move in A. thaliana, N.benthamiana and M. perfoliata. Accumulation of TuYV-GFP was however reduced when compared to the wild type virus. The impaired ability of the recombinant virus to reach efficiently non inoculated leaves is likely due to the insertion of the GFP sequence in the viral genome. The TuYVGFP genome was stable in N. benthamiana while it was subjected to partial deletions in A. thalianaand in M. perfoliata. Nevertheless, we observed fluorescent phloem cells in non-inoculated leaves of the three plant species. Importantly, fluorescent phloem cells were also observed after virus acquisition and inoculation by aphids, both in inoculated and non-inoculated leaves. This major breakthrough in the study of poleroviruses persistently transmitted by aphids will now be used to address whether the virus localisation in planta is affected following aphid infestation.

International audience

Specialization is an important attribute of a biological control agent. The maritime pine bast scale,Matsucoccus feytaudiDucasse (Hemiptera Matsucoccidae), is an invasive species in Southeast France and the North of Italy.Iberorhyzobius rondensisEizaguirre (Coleoptera: Coccinellidae), is a recently described ladybird species. Both adults and larvae are predaceous, feeding on egg masses ofM. feytaudi, and are strongly attracted toM. feytaudi’s sex pheromone. To evaluate the potential ofI. rondensisas a biocontrol agent of the scale, we studied its niche breadth and prey range with emphasis on pine forests and hemipterans as tested prey. In this study,I. rondensiswas found to achieve complete development only when fed onM. feytaudiegg masses (92.9% survival) and an artificial prey: eggs ofEphestia kuehniellaZeller (27.6% survival). From the 2nd instar onwards, complete development could be achieved using other prey species, although larvae had significantly higher mortality and slower development. In choice tests,M. feytaudiwas the preferred prey. Surveys of the ladybird populations in the Iberian Peninsula revealed that it was found exclusively onPinus pinasterAiton, the sole host ofM. feytaudi. The unusual specialization ofI. rondensis, among other predaceous ladybirds, makes it an appropriate candidate for classical biological control ofM. feytaudi.

International audience; In plants, roots are essential for water and nutrient acquisition. MicroRNAs (miRNAs) regulate their target mRNAs by transcript cleavage and/or inhibition of protein translation and are known as major post-transcriptional regulators of various developmental pathways and stress responses. In Arabidopsis thaliana, four isoforms of miR169 are encoded by 14 different genes and target diverse mRNAs, encoding subunits A of the NF-Y transcription factor complex. These miRNA isoforms and their targets have previously been linked to nutrient signalling in plants. By using mimicry constructs against different isoforms of miR169 and miR-resistant versions of NF-YA genes we analysed the role of specific miR169 isoforms in root growth and branching. We identified a regulatory node involving the particular miR169defg isoform and NF-YA2 and NF-YA10 genes that acts in the control of primary root growth. The specific expression of MIM169defg constructs altered specific cell type numbers and dimensions in the root meristem. Preventing miR169defg-regulation of NF-YA2 indirectly affected laterial root initiation. We also showed that the miR169defg isoform affects NF-YA2 transcripts both at mRNA stability and translation levels. We propose that a specific miR169 isoform and the NF-YA2 target control root architecture in Arabidopsis.

Main conclusion Drought-acclimated vines maintained higher gas exchange compared to irrigated controls under water deficit; this effect is associated with modified leaf turgor but not with improved petiole vulnerability to cavitation. A key feature for the prosperity of plants under changing environments is the plasticity of their hydraulic system. In the present research we studied the hydraulic regulation in grapevines (Vitis vinifera L.) that were first acclimated for 39 days to well-watered (WW), sustained water deficit (SD), or transient—cycles of dehydration–rehydration—water deficit (TD) conditions, and then subjected to varying degrees of drought. Vine development under SD led to the smallest leaves and petioles, but the TD vines had the smallest mean xylem vessel and calculated specific conductivity (k ts). Unexpectedly, both the water deficit acclimation treatments resulted in vines more vulnerable to cavitation in comparison to WW, possibly as a result of developmental differences or cavitation fatigue. When exposed to drought, the SD vines maintained the highest stomatal (g s) and leaf conductance (k leaf) under low stem water potential (Ψs), despite their high xylem vulnerability and in agreement with their lower turgor loss point (ΨTLP). These findings suggest that the down-regulation of k leaf and g s is not associated with embolism, and the ability of drought-acclimated vines to maintain hydraulic conductance and gas exchange under stressed conditions is more likely associated with the leaf turgor and membrane permeability. Electronic supplementary material The online version of this article (doi:10.1007/s00425-017-2662-3) contains supplementary material, which is available to authorized users.

International audience; Climate change is increasing mean temperatures and in the eastern Mediterranean is expected to decrease annual precipitation. The resulting increase in aridity may be too rapid for adaptation of tree species unless their gene pool already possesses variation in drought resistance. Vulnerability to embolism, estimated by the pressure inducing 50% loss of xylem hydraulic conductivity (P-50), is strongly associated with drought stress resistance in trees. Yet, previous studies on various tree species reported low intraspecific genetic variation for this trait, and therefore limited adaptive capacities to increasing aridity. Here we quantified differences in hydraulic efficiency (xylem hydraulic conductance) and safety (resistance to embolism) in four contrasting provenances of Pinus halepensis (Aleppo pine) in a provenance trial, which is indirect evidence for genetic differences. Results obtained with three techniques (bench dehydration, centrifugation and X-ray micro-CT) evidenced significant differentiation with similar ranking between provenances. Inter-provenance variation in P50 correlated with pit anatomical properties (torus overlap and pit aperture size). These results suggest that adaptation of P. halepensis to xeric habitats has been accompanied by modifications of bordered pit function driven by variation in pit aperture. This study thus provides evidence that appropriate exploitation of provenance differences will allow continued forestry with P. halepensis in future climates of the Eastern Mediterranean.