53161 research outputs found
Sort by
Genetic architecture of robustness in Capsicum annuum for resistance to Phytophthora capsici and Potato virus Y under a temperature stress
No full textAuthor correction: A rapid quality control test to foster the development of genetic control in mosquitoes
No full textA global synthesis reveals biodiversity-mediated benefits for crop production
No full textHuman land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society
Hydrodynamic Shape Changes Underpin Nuclear Rerouting in Branched Hyphae of an Oomycete Pathogen
No full textMultinucleate fungi and oomycetes are phylogenetically distant but structurally similar. To address whether they share similar nuclear dynamics, we carried out time-lapse imaging of fluorescently labeled Phytophthora palmivora nuclei. Nuclei underwent coordinated bidirectional movements during plant infection. Within hyphal networks growing in planta or in axenic culture, nuclei either are dragged passively with the cytoplasm or actively become rerouted toward nucleus-depleted hyphal sections and often display a very stretched shape. Benomyl-induced depolymerization of microtubules reduced active movements and the occurrence of stretched nuclei. A centrosome protein localized at the leading end of stretched nuclei, suggesting that, as in fungi, astral microtubule-guided movements contribute to nuclear distribution within oomycete hyphae. The remarkable hydrodynamic shape adaptations of Phytophthora nuclei contrast with those in fungi and likely enable them to migrate over longer distances. Therefore, our work summarizes mechanisms which enable a near-equal nuclear distribution in an oomycete. We provide a basis for computational modeling of hydrodynamic nuclear deformation within branched tubular networks. IMPORTANCE Despite their fungal morphology, oomycetes constitute a distinct group of protists related to brown algae and diatoms. Many oomycetes are pathogens and cause diseases of plants, insects, mammals, and humans. Extensive efforts have been made to understand the molecular basis of oomycete infection, but durable protection against these pathogens is yet to be achieved. We use a plant-pathogenic oomycete to decipher a key physiological aspect of oomycete growth and infection. We show that oomycete nuclei travel actively and over long distances within hyphae and during infection. Such movements require microtubules anchored on the centrosome. Nuclei hydrodynamically adapt their shape to travel in or against the flow. In contrast, fungi lack a centrosome and have much less flexible nuclei. Our findings provide a basis for modeling of flexible nuclear shapes in branched hyphal networks and may help in finding hard-to-evade targets to develop specific antioomycete strategies and achieve durable crop disease protection
Assimilation of Earth Observation Data Over Cropland and Grassland Sites into a Simple GPP Model
No full textThe application of detailed process-oriented simulation models for gross primary production (GPP) estimation is constrained by the scarcity of the data needed for their parametrization. In this manuscript, we present the development and test of the assimilation of Moderate Resolution Imaging Spectroradiometer (MODIS) satellite Normalized Difference Vegetation Index (NDVI) observations into a simple process-based model driven by basic meteorological variables (i.e., global radiation, temperature, precipitation and reference evapotranspiration, all from global circulation models of the European Centre for Medium-Range Weather Forecasts). The model is run at daily time-step using meteorological forcing and provides estimates of GPP and LAI, the latter used to simulate MODIS NDVI though the coupling with the radiative transfer model PROSAIL5B. Modelled GPP is compared with the remote sensing-driven MODIS GPP product (MOD17) and the quality of both estimates are assessed against GPP from European eddy covariance flux sites over crops and grasslands. Model performances in GPP estimation (R2 = 0.67, RMSE = 2.45 gC m-2 d-1, MBE = -0.16 gC m&-2 d-1) were shown to outperform those of MOD17 for the investigated sites (R2 = 0.53, RMSE = 3.15 gC m-2 d-1, MBE = -1.08 gC m-2 d-1)
Microbiota composition and functional profiling throughout the gastrointestinal tract of commercial weaning piglets
No full textDietary, environmental, and social stresses induced by weaning transition in pig production are associated with alterations of gut microbiota, diarrhea, and enteric infections. With the boom of-omic technologies, numerous studies have investigated the dynamics of fecal bacterial communities of piglets throughout weaning but much less research has been focused on the composition and functional properties of microbial communities inhabiting other gastrointestinal segments. The objective of the present study was to bring additional information about the piglet bacterial and archaeal microbiota throughout the entire digestive tract, both at the structural level by using quantitative PCR and high-throughput sequencing, and on functionality by measurement of short-chain fatty acids and predictions using Tax4Fun tool. Our results highlighted strong structural and functional differences between microbial communities inhabiting the fore and the lower gut as well as a quantitatively important archaeal community in the hindgut. The presence of opportunistic pathogens was also noticed throughout the entire digestive tract and could trigger infection emergence. Understanding the role of the intestinal piglet microbiota at weaning could provide further information about the etiology of post-weaning infections and lead to the development of effective preventive solutions
Exploring gene networks in two sunflower lines with contrasting leaf senescence phenotype using a system biology approach
No full textBackground Leaf senescence is a complex process, controlled by multiple genetic and environmental variables. In sunflower, leaf senescence is triggered abruptly following anthesis thereby limiting the capacity of plants to keep their green leaf area during grain filling, which subsequently has a strong impact on crop yield. Recently, we performed a selection of contrasting sunflower inbred lines for the progress of leaf senescence through a physiological, cytological and molecular approach. Here we present a large scale transcriptomic analysis using RNA-seq and its integration with metabolic profiles for two contrasting sunflower inbred lines, R453 and B481-6 (early and delayed senescence respectively), with the aim of identifying metabolic pathways associated to leaf senescence. Results Gene expression profiles revealed a higher number of differentially expressed genes, as well as, higher expression levels in R453, providing evidence for early activation of the senescence program in this line. Metabolic pathways associated with sugars and nutrient recycling were differentially regulated between the lines. Additionally, we identified transcription factors acting as hubs in the co-expression networks; some previously reported as senescence-associated genes in model species but many are novel candidate genes. Conclusions Understanding the onset and the progress of the senescence process in crops and the identification of these new candidate genes will likely prove highly useful for different management strategies to mitigate the impact of senescence on crop yield. Functional characterization of candidate genes will help to develop molecular tools for biotechnological applications in breeding crop yield
Mechanisms of drying-induced particle formation in solutions of dairy proteins:a multiscale approach
No full textSpray drying is a well-established process, but the phenomena ruling droplet-to-particle transition
remain black box, resulting in variable powder properties and drying performances. Therefore,
understanding precisely how the particle is formed and how to control its properties remain a major
challenge. This work aims to breakdown the complexity of the drying phenomena using an exploratory
multi-scale approach. Particle formation of different milk proteins (whey proteins and casein micelles) was
investigated using different experimental systems (single pendant droplet, mono-dispersed droplets and
spraying cone droplets) in controlled drying environments.
The results showed that the drying of a single protein droplet included three distinct stages
highlighting the occurrence of specific morphological events (constant rate shrinkage, buckling instability,
vacuole nucleation). According to the type of proteins, these stages differed in drying kinetics and droplet
dynamics, leading to characteristic and reproducible particle shapes irrespective of the droplet configuration
and the drying conditions. These different drying behaviors were related to specific skin formation
mechanisms at droplet air-liquid interface and consequent responses of the protein material to internal
stresses. In this work, we aimed at understanding how the different physico-chemical properties of whey
proteins (rigid globular shape) and casein micelles (deformable sponge-like structure) affect the mechanisms
of formation of such a skin, and from this the particle final shape.
However, the full understanding of the drying process of biocolloids is far to be achieved and,
notably, the impact of solute properties on the morphological characteristics of the evaporating droplets,
such as colloid segregation, skin formation and crack pattern development is not elucidated yet. To this aim,
the use of model colloidal solutions, whose rheological behavior is more easily deducible, could represent a
significant boost. Consequently, we compared the drying of droplets of whey proteins and casein micelles to
that of dispersions of silica particles and polymer-coated silica particles, respectively. The mechanical
behavior of such biological colloids and model silica dispersions was investigated through the analysis of
crack formation, and the measurements of their mechanical properties using indentation testing. The study
reveals numerous analogies between dairy and corresponding model systems, thus confirming these latter as
powerful tools to highlight the signature of the matter on the drying process and at the molecular scale.
The outcomes presented in this work represent a first step to shed light on the physics of drying
dairy droplets; they open the road to further investigation about mixes of milk proteins. Moreover, the
observation of mixtures of dairy colloids would contribute to improve the knowledge about the evaporation
of colloidal polydisperse systems, which represents a current scientific challenge
Root Architectural Trait Diversity in Aubergine (Solanum melongena L.) and Related Species and Correlations with Plant Biomass
No full textBackground: We investigated root architecture and plant biomass traits of 25 aubergine genepool accessions representative of 9 Solanum L. species, including S. melongena L., grown at two sites in South-East
France in order to quantify the diversity of root phenotypes, identify correlations between traits and determine the influence of the environment on trait stability.
Method: Aubergine seeds were sown in a mixture of sieved compost and vermiculite in 1m high PVC tubes of 10 cm diameter. Roots and aerial parts were harvested after 4–5 weeks growth. Measured root traits included: root depth and root growth rate, maximum apical diameter, minimum apical diameter, the ratio of daughter to mother root apical diameter, and root inter-lateral distance.
Results:
• Root maximum diameter and inter-lateral distance showed the largest phenotypic variability between the accessions of S. melongena as well as between the 9 Solanum species.
• Most traits were significantly affected by the experimental site except root maximum diameter and shoot dry weight accumulation per day. For most traits there was an interaction between the genotype and the site.
• Maximum root diameter and the ratio of daughter to mother root diameter are not correlated with other traits whereas root inter-lateral distance correlates with several traits including root fresh weight.
Conclusions: Root architectural traits show diversity within S. melongena and between S. melongena and related species. We confirm that root maximum diameter one of the traits with the highest heritability, i.e., depends on the genotype and is stable in different environments and that root inter-lateral distance is a plastic trait affected by the environment. The study gives some indications on accessions that could be chosen as
rootstocks
The nirification inhibitor vizura (R) reduces n2o emissions when added to digestate before Injection under irrigated maize in the po valley (northern italy)
No full textThe agricultural area in the Po Valley is prone to high nitrous oxide (N2O) emissions as it is characterized by irrigated maize-based cropping systems, high amounts of nitrogen supplied, and elevated air temperature in summer. Here, two monitoring campaigns were carried out in maize fertilized with raw digestate in a randomized block design in 2016 and 2017 to test the effectiveness of the 3, 4 DMPP inhibitor Vizura (R) on reducing N2O-N emissions. Digestate was injected into 0.15 m soil depth at side-dressing (2016) and before sowing (2017). Non-steady state chambers were used to collect N2O-N air samples under zero N fertilization (N0), digestate (D), and digestate + Vizura (R) (V). Overall, emissions were significantly higher in the D treatment than in the V treatment in both 2016 and 2017. The emission factor (EF, %) of V was two and four times lower than the EF in D in 2016 and 2017, respectively. Peaks of NO3-N generally resulted in N2O-N emissions peaks, especially during rainfall or irrigation events. The water-filled pore space (WFPS, %) did not differ between treatments and was generally below 60%, suggesting that N2O-N emissions were mainly due to nitrification rather than denitrification