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A whole genome scan of SNP data suggests a lack of abundant hard selective sweeps in the genome of the broad host range plant pathogenic fungus Sclerotinia sclerotiorum
No full textA New Role for SAG12 Cysteine Protease in Roots of Arabidopsis thaliana
No full textSenescence associated gene (SAG) 12, which encodes a cysteine protease is considered to be important in nitrogen (N) allocation to Arabidopsis thaliana seeds. A decrease in the yield and N content of the seeds was observed in the Arabidopsis SAG12 knockout mutants (sag12) relative to the wild type (Col0) under limited nitrogen nutrition. However, leaf senescence was similar in both lines. To test whether SAG12 is involved in N remobilization from organs other than the leaves, we tested whether root N could be used in N mobilization to the seeds. Root architecture, N uptake capacity and 15N partitioning were compared in the wild type and sag12 under either high nitrogen (HN) or low nitrogen (LN) conditions. No differences in root architecture or root N uptake capacity were observed between the lines under HN or LN. However, under LN conditions, there was an accumulation of 15N in the sag12 roots compared to the wild type with lower allocation of 15N to the seeds. This was accompanied by an increase in root N protein contents and a significant decrease in root cysteine protease activity. SAG12 is expressed in the root stele of the plants at the reproductive stage, particularly under conditions of LN nutrition. Taken together, these results suggest a new role for SAG12. This cysteine protease plays a crucial role in root N remobilization that ensures seed filling and sustains yields when nitrogen availability is low
Agrobranche, give a green value to the agroforestry branches
No full textAgrobranche aims at studying the possibility of strengthening the economic model of the agroforestry by improving the valuation of the intermediate biomass in the new domains of bio-based materials and chemistry. This objective answers a double purpose: Agroforestry management requires regular cuttings of branches for the control of the shade and the influence of trees. Branches constitute a resource available throughout the life of trees, very few harvested today. For the partners of the industrial development, it is the possibility to benefit a resource of quality compatible with the classic agricultural productions, and safer in terms of supply. Agrobranche will identify the best segments for the agroforestry systems with a comparison between the various uses and to dread the relevance of these agroforestry products among the set of resources mobilizable for these segments. Among the aimed segments, rigid / semi-rigides insulations with wood, particle boards and composites wood-polymer for the « material » way and extractibles molecules for the «green chemistry» way will be particularly envisaged as ways of promising valuations. The works which are going to be led by our consortium including agricultural professional organizations, research laboratories and companies, aim in : Defining agroforestry products likely to contain substances extractibles of interest, Qualifying the industrial potential of valuation of the agroforestry chips for the new markets Identifying the standard of the agroforestry chips meeting the needs of companies for a given application and an organization of the sector to optimize its development and profitability, defining on one hand the upstream chips production ways and on the other hand the downstream technological ways dedicated for fibers and molecules extraction, The main asset of Agrobranche is the concern to connect the needs between research and industrial sectors with an agroforestry product with strong agroecological value, without any competition for the agricultural productions. By this way, we avoid the frequent stumbling block of the green chemistry projects based on rival productions and\or on limited resources or little long-lasting, even few sustainable from an energical point of view
A tool to guide the selection of impact categories for LCA studies by using the representativeness index
No full textUnderstanding the environmental profile of a product computed from the Life Cycle Assessment (LCA) framework is sometimes challenging due to the high number of environmental indicators involved. The objective here, in guiding interpretation of LCA results, is to highlight the importance of each impact category for each product alternative studied. For a given product, the proposed methodology identifies the impact categories that are worth focusing on, relatively to a whole set of products from the same cumulated database. The approach extends the analysis of Representativeness Indices (RI) developed by Esnouf et al. (2018). It proposes a new operational tool for calculating RIs at the level of impact categories for a Life Cycle Inventory (LCI) result. Impact categories and LCI results are defined as vectors within a standardized vector space and a procedure is proposed to treat issues coming from the correlation of impact category vectors belonging to the same Life Cycle Impact Assessment (LCIA) method. From the cumulated ecoinvent database, LCI results of the Chinese and the German electricity mixes illustrate the method. Relevant impact categories of the EU-standardized ILCD method are then identified. RI results from all products of a cumulated LCI database were therefore analysed to assess the main tendencies of the impact categories of the ILCD method. This operational approach can then significantly contribute to the interpretation of the LCA results by pointing to the specificities of the inventories analysed and for identifying the main representative impact categories
Earthworms mitigate pesticide effects on soil microbial activities
No full textEarthworms act synergistically with microorganisms in soils. They are ecosystem engineers involved in soil organic matter degradation and nutrient cycling, leading to the modulation of resource availability for all soil organisms. Using a soil microcosm approach, we aimed to assess the influence of the earthworm Aporrectodea caliginosa on the response of soil microbial activities against two fungicides, i.e. Cuprafor micro® (copper oxychloride, a metal) and Swing® Gold (epoxiconazole and dimoxystrobin, synthetic organic compounds). The potential nitrification activity (PNA) and soil enzyme activities (glucosidase, phosphatase, arylamidase, and urease) involved in biogeochemical cycling were measured at the end of the incubation period, together with earthworm biomass. Two common indices of the soil biochemistry were used to aggregate the response of the soil microbial functioning: the geometric mean (Gmean) and the Soil Quality Index (SQI). At the end of the experiment, the earthworm biomass was not impacted by the fungicide treatments. Overall, in the earthworm-free soil microcosms, the two fungicides significantly increased several soil enzyme and nitrification activities, leading to a higher GMean Index as compared to the non-treated control soils. The microbial activity responses depended on the type of activity (nitrification was the most sensitive one), on the fungicide (Swing® Gold or Cuprafor micro®), and on the doses. The SQI indices revealed higher effects of both fungicides on the soil microbial activity in the absence of earthworms. The presence of earthworms enhanced all soil microbial activities in both the control and fungicide-contaminated soils. Moreover, the magnitude of the fungicide impact, integrated through the SQI index, was mitigated by the presence of earthworms, conferring a higher stability of microbial functional diversity. Our results highlight the importance of biotic interactions in the response of indicators of soil functioning (i.e., microbial activity) to pesticides
Fruit salad in the lab: comparing botanical species to help deciphering fruit primary metabolism
No full textAlthough fleshy fruit species are economically important worldwide and crucial for human nutrition, the regulation of their fruit metabolism remains to be described finely. Fruit species differ in the origin of the tissue constituting the flesh, duration of fruit development, coordination of ripening changes (climacteric vs. non-climacteric type) and biochemical composition at ripeness is linked to sweetness and acidity. The main constituents of mature fruit result from different strategies of carbon transport and metabolism. Thus, the timing and nature of phloem loading and unloading can largely differ from one species to another. Furthermore, accumulations and transformations of major soluble sugars, organic acids, amino acids, starch and cell walls are very variable among fruit species. Comparing fruit species therefore appears as a valuable way to get a better understanding of metabolism. On the one hand, the comparison of results of studies about species of different botanical families allows pointing the drivers of sugar or organic acid accumulation but this kind of comparison is often hampered by heterogeneous analysis approaches applied in each study and incomplete dataset. On the other hand, cross-species studies remain rare but have brought new insights into key aspects of primary metabolism regulation. In addition, new tools for multi-species comparisons are currently emerging, including meta-analyses or re-use of shared metabolic or genomic data, and comparative metabolic flux or process-based modeling. All these approaches contribute to the identification of the metabolic factors that influence fruit growth and quality, in order to adjust their levels with breeding or cultural practices, with respect to improving fruit traits
SMART - Agroforesterie maraîchère : un choix stratégique pour garantir une durabilité en transition agroécologique ?
No full textEn France, actuellement, parmi les différentes formes d'agroforesterie, les combinaisons spatiales
d'arbres fruitiers et de cultures maraîchères connaissent actuellement une forte croissance. Le projet
SMART, qui a réuni plusieurs équipes de recherche et organismes de développement, visait à
comprendre ces systèmes en tenant compte des dimensions technique, agronomique et socioéconomique. Les résultats des enquêtes et observations réalisées auprès des agriculteurs associés à
ce projet ont montré que ces systèmes concernent principalement des exploitations agricoles engagées
dans des chaînes d'approvisionnement alimentaire courtes pour lesquelles la diversité des produits est
un élément central de la stratégie commerciale et de la performance. SMART a également cherché à
évaluer les effets des synergies et des compétitions entre arbres fruitiers et maraîchage, tels que
perçus par les agriculteurs. La grande majorité d'entre eux considèrent que la culture intercalaire
d'arbres fruitiers et de légumes ne pose pas de problème majeur en termes d'organisation du travail.
Cependant, l’imbrication des légumes et des fruitiers peut entraîner des pics de travail conjoints et une
augmentation de la complexité en termes de gestion des productions qui ne sont pas à négliger. Cela
plaide pour une réflexion fine sur la conception du système en amont et l’acquisition de compétences
spécifiques aux deux ateliers. Les producteurs ont estimé que l’agroforesterie ne crée pas de
concurrence susceptible d'avoir un impact négatif sur la productivité des cultures. Leurs certitudes
concernant ces différentes dimensions étaient plutôt limitées, ce de par la durée généralement courte
de leur expérience. Cependant, l'évaluation a conduit la plupart d'entre eux à considérer que le choix de
l'agroforesterie était pleinement justifié et pouvait être recommandé à d'autres maraîchers. Ces
premiers résultats ont montré la nécessité, lors de l'évaluation de tels systèmes, d'adopter un point de
vue dynamique et holistique sur les différents niveaux de performance. Il est primordial de considérer
l'évolution des compromis réalisés chemin faisant entre les avantages et les inconvénients de ce type
d'agroforesterie sur le long terme.In France, among various forms of agroforestry, farming systems combining spatially fruit trees and
market gardening vegetables are currently gaining ground. The 'SMART' project, bringing together
various research teams and extension services, aimed at understanding such systems considering
technical, agronomic and socio-economic dimensions. Surveys and observations carried out with involved farmers showed that most of them are integrated in short supply chains where the diversity of
products is a key factor of both marketing strategy and performance. SMART also assessed synergy
and competition effects between fruit trees and vegetables, as perceived by farmers. Most farmers
consider that intercropping fruit trees and vegetables does not raise major issues as far as work
organisation is concerned. However, mixing vegetables and trees can lead to joint workload peaks and
increased management complexity, which are not to be neglected. This advocates for a fine-tuned
design of the system beforehand and highlights the necessity for farmers to get specific skills for both
production types. Farmers estimate that agroforestry does not negatively impact crop productivity. Their
level of certainty about abovementioned dimensions is rather limited because their experience is
generally short. Nevertheless, most of them consider that going for agroforestry was fully justified and
could be recommended to other market gardeners. These early results have stressed the necessity of
assessing the different types of performances of such systems with a dynamic and holistic perspective.
It is crucial to consider on the long run the evolution of trade-offs that farmers make along the way
between advantages and drawbacks of this type of agroforestry
Milk proteome from in silico data aggregation allows the identification of putative biomarkers of negative energy balance in dairy cows
No full textA better knowledge of the bovine milk proteome and its main drivers is a prerequisite for the modulation of bioactive proteins in milk for human nutrition, as well as for the discovery of biomarkers that are useful in husbandry and veterinary medicine. Milk composition is affected by lactation stage and reflects, in part, the energy balance of dairy cows. We aggregated the cow milk proteins reported in 20 recent proteomics publications to produce an atlas of 4654 unique proteins. A multistep assessment was applied to the milk proteome datasets according to lactation stages and milk fractions, including annotations, pathway analysis and literature mining. Fifty-nine proteins were exclusively detected in milk from early lactation. Among them, we propose six milk proteins as putative biomarkers of negative energy balance based on their implication in metabolic adaptative pathways. These proteins are PCK2, which is a gluconeogenic enzyme; ACAT1 and IVD, which are involved in ketone metabolism; SDHA and UQCRC1, which are related to mitochondrial oxidative metabolism; and LRRC59, which is linked to mammary gland cell proliferation. The cellular origin of these proteins warrants more in-depth research but may constitute part of a molecular signature for metabolic adaptations typical of early lactation