eKhSACIR інституційному репозитарії Харківської державної академії культури
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Varying applicability of four different satellite-derived soil moisture products to global gridded crop model evaluation
No full textInternational audienceSatellite-derived daily surface soil moisture products have been increasingly available, but their applicability to global gridded crop model (GGCM) evaluation is unclear. This study compares four different soil moisture products with the flux tower site observation at 18 cropland sites across the world where either of maize, soybean, rice and wheat is grown. These products include the first and second versions of Climate Change Initiative Soil Moisture (CCISM-1 and CCISM-2) datasets distributed by the European Space Agency and two different AMSR-E (Advanced Microwave Scanning Radiometer–Earth Observing System)-derived soil moisture datasets, separately provided by the Japan Aerospace Exploration Agency (AMSRE-J) and U.S. National Aeronautics and Space Administration (AMSRE-N). The comparison demonstrates varying reliability of these products in representing major characteristics of temporal pattern of cropland soil moisture by product and crop. Possible reasons for the varying reliability include the differences in sensors, algorithms, bands and criteria used when estimating soil moisture. Both the CCISM-1 and CCISM-2 products appear the most reliable for soybean- and wheat-growing area. However, the percentage of valid data of these products is always lower than other products due to relatively strict criteria when merging data derived from multiple sources, although the CCISM-2 product has much more data with valid retrievals than the CCISM-1 product. The reliability of the AMSRE-J product is the highest for maize- and rice-growing areas and comparable to or slightly lower than the CCISM products for soybean- and wheat-growing areas. The AMSRE-N is the least reliable in most location-crop combinations. The reliability of the products for rice-growing area is far lower than that of other upland crops likely due to the extensive use of irrigation and patch distribution of rice paddy in the area examined here. We conclude that the CCISM-1, CCISM-2 and AMSRE-J products are applicable to GGCM evaluation, while the AMSRE-N product is not. However, we encourage users to integrate these products with in situ soil moisture data especially when GGCMs simulations for rice are evaluated
Analysis of young Miscanthus x giganteus yield variability: a survey of farmers' fields in east central France
No full textMiscanthus x giganteus is often regarded as one of the most promising crops to produce bioenergy because it is renowned for its high biomass yields, combined with low input requirements. However, its productivity has been mainly studied in experimental conditions. Our study aimed at characterizing and explaining young M.giganteus yield variability on a farmers' field network located in the supply area of a cooperative society in east central France. It included the first three growth years of the crop. We defined and calculated a set of indicators of limiting factors that could be involved in yield variations and used the mixed-model method to identify those explaining most of the yield variation. Commercial yields averaged 8.1 and 12.8 t DM ha(-1) for the second and third growth year, respectively. However, these mean results concealed a high variability, ranging from 3 to 19 t DM ha(-1). Commercial yields, measured on whole fields, were on average 20% lower than plot yields, measured on a small area (two plots of 25 m(2)). Yields were found to be much more related to shoot density than to shoot mass, and particularly to the shoot density established at the end of the planting year. We highlighted that planting success was decisive and was built during the whole plantation year. Fields with the lowest yields also had the highest weed cover, which was influenced by the distance between the field and the farmhouse, the preceding crop and the soil type. Our findings show that growing young M.giganteus on farmers' fields involves limiting factors different from those commonly reported in the literature for experimental conditions and they could be useful to assess the economic and environmental impacts of growing M.giganteus on farmers' fields. They could also stimulate the discussion about growing bioenergy crops on marginal lands
The biofilm lifestyle involves an increase in bacterial membrane saturated fatty acids
No full textBiofilm formation on contact surfaces contributes to persistence of foodborne pathogens all along the food and feed chain. The specific physiological features of bacterial cells embedded in biofilms contribute to their high tolerance to environmental stresses, including the action of antimicrobial compounds. As membrane lipid adaptation is a vital facet of bacterial response when cells are submitted to harsh or unstable conditions, we focused here on membrane fatty acid composition of biofilm cells as compared to their free-growing counterparts. Pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium) were cultivated in planktonic or biofilm states and membrane fatty acid analyses were performed on whole cells in both conditions. The percentage of saturated fatty acids increases in biofilm cells in all cases, with a concomitant decrease of branched-chain fatty acids for Gram-positive bacteria, or with a decrease in the sum of other fatty acids for Gram-negative bacteria. We propose that increased membrane saturation in biofilm cells is an adaptive stress response that allows bacteria to limit exchanges, save energy, and survive. Reprogramming of membrane fluidity in biofilm cells might explain specific biofilm behavior including bacterial recalcitrance to biocide action
Phytophthora nicotianae diseases worldwide: new knowledge of a long-recognised pathogen
No full textInternational audiencePhytophthora nicotianae was first isolated from tobacco at the end of the 19th century. This organism is now considered as one of the most devastating oomycete plant pathogens, with a recognized host range of more than 255 species over five continents and a wide diversity of climates. The economic losses caused by P. nicotianae are difficult to estimate, because of the diversity of its hosts and ecological niches. For these reasons, this pathogen represents a continuous challenge to plant disease management programmes, which frequently rely solely on the use of chemicals. Phytophthora nicotianae is better adapted than its competitors to abiotic stresses, especially to climate warming. As a result, its importance is increasing. This review illustrates, with some examples, how P. nicotianae currently impacts plant economies worldwide, and how it may constitute more severe threats to agriculture and natural ecosystems in the context of global climate change
Limited gene dispersal and spatial genetic structure as stabilizing factors in an ant-plant mutualism
No full textInternational audienceComparative studies of the population genetics of closely associated species are necessary to properly understand the evolution of these relationships because gene flow between populations affects the partners' evolutionary potential at the local scale. As a consequence (at least for antagonistic interactions), asymmetries in the strength of the genetic structures of the partner populations can result in one partner having a co-evolutionary advantage. Here, we assess the population genetic structure of partners engaged in a species-specific and obligatory mutualism: the Neotropical ant-plant, Hirtella physophora, and its ant associate, Allomerus decemarticulatus. Although the ant cannot complete its life cycle elsewhere than on H. physophora and the plant cannot live for long without the protection provided by A. decemarticulatus, these species also have antagonistic interactions: the ants have been shown to benefit from castrating their host plant and the plant is able to retaliate against too virulent ant colonies. We found similar short dispersal distances for both partners, resulting in the local transmission of the association and, thus, inbred populations in which too virulent castrating ants face the risk of local extinction due to the absence of H. physophora offspring. On the other hand, we show that the plant populations probably experienced greater gene flow than did the ant populations, thus enhancing the evolutionary potential of the plants. We conclude that such levels of spatial structure in the partners' populations can increase the stability of the mutualistic relationship. Indeed, the local transmission of the association enables partial alignments of the partners' interests, and population connectivity allows the plant retaliation mechanisms to be locally adapted to the castration behaviour of their symbionts
TIR1/AFB-Aux/IAA auxin perception mediates rapid cell wall acidification and growth of Arabidopsis hypocotyls
No full textDespite being composed of immobile cells, plants reorient along directional stimuli. The hormone auxin is redistributed in stimulated organs leading to differential growth and bending. Auxin application triggers rapid cell wall acidification and elongation of aerial organs of plants, but the molecular players mediating these effects are still controversial. Here we use genetically-encoded pH and auxin signaling sensors, pharmacological and genetic manipulations available for Arabidopsis etiolated hypocotyls to clarify how auxin is perceived and the downstream growth executed. We show that auxin-induced acidification occurs by local activation of H+-ATPases, which in the context of gravity response is restricted to the lower organ side. This auxin-stimulated acidification and growth require TIR1/AFB-Aux/IAA nuclear auxin perception. In addition, auxin-induced gene transcription and specifically SAUR proteins are crucial downstream mediators of this growth. Our study provides strong experimental support for the acid growth theory and clarified the contribution of the upstream auxin perception mechanisms
INRA Feed Unit System for Ruminants: a new ‘Red Book’
No full textSession 40. The role of feed evaluation systems in feeding our livestock tomorrowInternational audienceThe INRA feed unit system for ruminants, widely adopted in France and several countries, has been regularly updated. But some limits appeared regarding emerging challenges for animal nutrition: prediction of feed efficiency, product quality, effect of feeding on animal health and emissions to the environment. It also did not properly cover the use of low-quality or high-concentrate diets. To address these issues, a group of INRA researchers involved in ruminant nutrition was estabished in 2010 to work on the ‘Systali’ project. The system has been renewed using meta-analyses (large data bases of digestion, metabolic balance and animal performance, representative of the major feeding practices), and modelling with evaluations and simulations. The dietary supply model has been renewed to account for digestive interactions and flows of individual nutrients (VFA, glucose, AA, LCFA). Feed values are no longer additive and depend on the final ration. Requirements have been updated to account for variability in metabolic efficiency and new ration values, and various productive and non-productive animal responses to diets have been modeled. The main advances are presented in a new ‘Red book’, the ‘INRA Feed Unit System for Ruminants’ (Wageningen Academic Publishers), organised in 4 parts. The first two parts present biological concepts and equations (with their field of application and statistical precision) used to predict intake (including at pasture) and nutrient supply (Part 1), animal requirements and responses to diets (Part 2). They apply to net energy, metabolisable protein and amino acids, but also water, minerals and vitamins. Part 3 presents the use of concepts and equations in rationing with two purposes: (1) diet calculation of a given performance objective; and (2) prediction of the multiple responses of animal to diet changes in the case of dairy and meat, large and small ruminant productions. Part 4 provides tables of feed values, and their prediction. For each part, specificities for tropical and Mediterranean areas are presented. All the equations and concepts will be embedded in the INR@tion software available on the internet for practical use
Differences in digestibility between cows contribute to explain differences in feed efficiency
No full textSession 72 Theatre 6International audienceResidual Feed Intake (RFI) is a feed efficiency (FE) trait phenotypically independent of body weight and level of production. It reflects inherent between-animal variations in biological determinants of FE. Among these determinants, differences in digestion have been suggested but it may rely on the type of diets used. We tested the hypothesis of a higher digestibility in more efficient cows (low RFI) regardless of the type of diets. The objective of this study was to determine the apparent digestibility of dry matter (DMd) of high (NDF=62%) and low fibre (NDF=39%) diets in simultaneously 2 RFI divergent groups of 8 non-pregnant non-lactating Charolais cows (RFI-: -0.73±0.59, 705±96 kg and RFI+: 1.02±0.34, 711±78 kg). RFI was measured when cows were heifers (21 months old) during 12 weeks on herb silage (cultivated fescue) diet distributed ad libitum. Four periods (P) of digestion trials were carried out successively using either high (100% hay, P1 and P2) or low fibre diet (maize silage/concentrate, 67/33, P3 and P4). Each period lasted 2-3 weeks ad libitum followed by 7 days of total faeces collection at 95% ad libitum. DMd was calculated using dry matter intake (DMI) and feacal dry matter excretion. The intra period individual range of variation of DMI and DMd were closed to 4 kg/d and 6 to 8 g/100 g for both diets respectively. Differences between RFI groups were significant for DMd (P=0.024) and not for DMI (P=0.27). RFI-cows presented higher DMd than RFI+ cows for diets (61.0±1.81% vs 60.0±2.1% for high-fibre diet and 69.6±1.96% vs 68.3±1.82% for low-fibre diet). This study showed that on average feed efficient cows (RFI-) had higher digestive efficiency than non-efficient cows (RFI+) regardless of the type of diets used
Résistance génétique à l'entérite chez la truite ? Interaction avec la flavobactériose et les caractères de production
No full textNational audienceL’entérite est une maladie bactérienne pouvant induire des mortalités importantes durant le période estivale, surtout en production de grande truite. Une des principales causes proposées est la substitution par le tourteau de soja qui aurait un effet abrasif sur le tube digestif. L’entérite est principalement combattue par une réduction drastique du taux d’alimentation durant la période estivale, des traitements antibiotiques et de nouvelles formulations d’aliments tentant de limiter les atteintes à la muqueuse intestinale. Les mortalités n’étant pas totales, Bretagne Truite a recherché dans le cadre du projet RE-SIST l’existence d’une variabilité génétique sélectionnable ainsi que les éventuelles corrélations génétiques avec la résistance à la flavobactériose et avec les performances de croissance et les rendements de découpe.600 familles ont été créées en novembre 2013 par croisement de 98 mères avec 99 néomâles. Deux lots de 2000 sujets chacun ont été respectivement soumis à des challenges naturels en pisciculture (printemps 2014) et à l’entérite (été 2014 et début d’été 2015) à la pisciculture de Keryas. Un 3ème lot de 2000 a été abattu au poids commercial (atelier Bretagne Truite, Plouigneau) pour mesurer performances de croissance, de rendement de découpe et de teneur en lipides de la chair (Torry Fish Fat Meter). Le 2ème et le 3ème lot ont été nourris avec un aliment commercial (Skretting Omega HE A25SF). Les animaux ont été assignés à leurs parents par génotypage de marqueurs microsatellites.La mortalité par flavobactériose a été de 84.3 % et celle par entérite de 23.2 %. Les héritabilités de ces deux caractères sont estimées à 0,31 ± 0,04 et 0.42 ± 0.04 et la corrélation génétique à 0.01 ± 0,11. Les héritabilités du poids à l’abattage et des caractères qualitatifs sont estimées entre 0.24 ± 0,04 et 0.54 ± 0,05 La résistance à la flavobactériose présente une corrélation génétique positive avec le poids (0.25 ± 0,09) contrairement la résistance à l’entérite (rA= -0.35 ± 0,10). La résistance à ces pathologies est globalement indépendante des caractères de découpe ou de teneur en lipides des filets.La résistance à l’entérite est héritable (0.42) mais corrélée négativement avec la croissance de façon suffisamment limitée (-0.35) permettant d’envisager une sélection conjointe. Ces résultats permettent d’avancer que le risque associé à la substitution par le soja est d’autant plus important que l’ingéré est augmenté par l’utilisation de génotypes à plus forte croissance. La sélection de sujets plus résistants à l’entérite sur une alimentation plus substituée pourrait permettre de sélectionner de futurs génotypes moins sensibles au tourteau de soja et donc de réduire les pertes de productivité liées à la sous-exploitation actuelle du potentiel de croissance. Enfin, la corrélation nulle avec la sensibilité à la flavobactériose montre que l’amélioration de la résistance combinée à ces deux pathogènes est possible
1ères Rencontres Francophones sur les Légumineuses RFL (membres du comité d’organisation logistique)
No full textBAP GEAPSI SAR UMRNational audienc