The phenome analysis of mutant alleles in Leucine-Rich Repeat Receptor-Like Kinase genes in rice reveals new potential targets for stress tolerant cereals

AbstractPlants are constantly exposed to a variety of biotic and abiotic stresses that reduce their fitness and performance. At the molecular level, the perception of extracellular stimuli and the subsequent activation of defense responses require a complex interplay of signaling cascades, in which protein phosphorylation plays a central role. Several studies have shown that some members of the Leucine-Rich Repeat Receptor-Like Kinase (LRR-RLK) family are involved in stress and developmental pathways. We report here a systematic analysis of the role of the members of this gene family by mutant phenotyping in the monocotyledon model plant rice, Oryza sativa. We have then targeted 176 of the ∼320 LRR-RLK genes (55.7%) and genotyped 288 mutant lines. Position of the insertion was confirmed in 128 lines corresponding to 100 LRR-RLK genes (31.6% of the entire family). All mutant lines harboring homozygous insertions have been screened for phenotypes under normal conditions and under various abiotic stresses. Mutant plants have been observed at several stages of growth, from seedlings in Petri dishes to flowering and grain filling under greenhouse conditions. Our results show that 37 of the LRR-RLK rice genes are potential targets for improvement especially in the generation of abiotic stress tolerant cereals

Occurrence of pesticide residues in indoor dust of farmworker households across Europe and Argentina.

Pesticides are widely used as plant protection products (PPPs) in farming systems to preserve crops against pests, weeds, and fungal diseases. Indoor dust can act as a chemical repository revealing occurrence of pesticides in the indoor environment at the time of sampling and the (recent) past. This in turn provides information on the exposure of humans to pesticides in their homes. In the present study, part of the Horizon 2020 funded SPRINT project, the presence of 198 pesticide residues was assessed in 128 indoor dust samples from both conventional and organic farmworker households across Europe, and in Argentina. Mixtures of pesticide residues were found in all dust samples (25-121, min-max; 75, median). Concentrations varied in a wide range (<0.01 ng/g-206 μg/g), with glyphosate and its degradation product AMPA, permethrin, cypermethrin and piperonyl butoxide found in highest levels. Regarding the type of pesticides, insecticides showed significantly higher levels than herbicides and fungicides. Indoor dust samples related to organic farms showed a significantly lower number of residues, total and individual concentrations than those related to conventional farms. Some pesticides found in indoor dust were no longer approved ones (29 %), with acute/chronic hazards to human health (32 %) and with environmental toxicity (21 %)

Pesticide residues with hazard classifications relevant to non-target species including humans are omnipresent in the environment and farmer residences

Intensive and widespread use of pesticides raises serious environmental and human health concerns. The presence and levels of 209 pesticide residues (active substances and transformation products) in 625 environmental samples (201 soil, 193 crop, 20 outdoor air, 115 indoor dust, 58 surface water, and 38 sediment samples) have been studied. The samples were collected during the 2021 growing season, across 10 study sites, covering the main European crops, and conventional and organic farming systems. We profiled the pesticide residues found in the different matrices using existing hazard classifications towards non-target organisms and humans. Combining monitoring data and hazard information, we developed an indicator for the prioritization of pesticides, which can support policy decisions and sustainable pesticide use transitions. Eighty-six percent of the samples had at least one residue above the respective limit of detection. One hundred residues were found in soil, 112 in water, 99 in sediments, 78 in crops, 76 in outdoor air, and 197 in indoor dust. The number, levels, and profile of residues varied between farming systems. Our results show that non-approved compounds still represent a significant part of environmental cocktails and should be accounted for in monitoring programs and risk assessments. The hazard profiles analysis confirms the dominance of compounds of low-moderate hazard and underscores the high hazard of some approved compounds and recurring “no data available” situations. Overall, our results support the idea that risk should be assessed in a mixture context, taking environmentally relevant mixtures into consideration. We have uncovered uncertainties and data gaps that should be addressed, as well as the policy implications at the EU approval status level. Our newly introduced indicator can help identify research priority areas, and act as a reference for targeted scenarios set forth in the Farm to Fork pesticide reduction goals

Home conservation strategies for tomato (Solanum lycopersicum): Storage temperature vs. duration – Is there a compromise for better aroma preservation?

International audienceExpression of dissatisfaction with tomato aroma prompted us to lead this study on the impact of domestic storage conditions on volatile compounds. Two storage modalities (20 and 4 °C) and two cultivars (Levovil and LCx) were used. Volatile compounds were analysed by gas chromatography–mass spectrometry detection after accelerated solvent extraction. Physical characteristics, lipoxygenase activity, hydroperoxide lyase activity; linoleic acid and linolenic acid were monitored. Storing tomatoes at 4 °C induced a drastic loss in volatiles, whatever their biosynthetic origin. After 30 days at 4 °C, the concentration of volatiles had decreased by 66%. Reconditioning for 24 h at 20 °C was able to recover some aroma production after up to 6 days storage at 4 °C. Volatile degradation products arising from carotenoids and amino acids increased when tomatoes were kept at 20 °C, while lipid degradation products did not vary. Storing tomatoes at fridge temperature, even for short durations, was detrimental for their aroma. This should be taken into account to formulate practical advice for consumers

The distribution of H2O between silicate melt and nominally anhydrousperidotiteandtheonsetofhydrousmelting in thedeepuppermantle

International audienceThe partitioningofH2O betweenamantleperidotiteassemblageandlowdegreehydrousmelthas beeninvestigatedat6GPa(correspondingto ∼180kmdepth)atatemperatureof1400 ◦C. Peridotite mineralphaseswereanalysedfrom6meltingexperimentsperformedinanaturalchemicalsystem.The experimentscontained ∼80wt%ofalowdegreehydrousmeltthatwasobtainedthroughaseriesof experimentswherethemeltcompositionwasiterativelyadjusteduntilsaturationwiththeappropriate peridotiteassemblagewasachieved.Themeltisfluid-undersaturatedattheconditionsoftheexperiment. Ion microprobemeasurementsofthemineralphasesindicateolivineH2O concentrationsof434 ± 61 ppmwtandaverageclinopyroxene(cpx)concentrationsof1268 ± 173 ppmwtH2O. Orthopyroxene (opx) andgarnetcontain700 ± 46 ppmwtand347 ± 83 ppmwtH2O, respectively.TheH2O contentof the hydrousmeltswasdeterminedbymassbalancetobe11 ± 0.5 wt%H2O. H2O partitioncoefficients betweenmineralsandmelt(Dmin/melt H2O = Xmin H2O/Xmelt H2O ) are0.0040±0.0006 forolivine,0.0064±0.0004 for opx, 0.0115±0.0016 forcpxand0.0032±0.0008 forgarnet. Using thedeterminedH2O partitioncoefficientstheonsetandextentofmeltingatconditionsequivalent to180kmbelowmid-oceanridgeswasdeterminedasafunctionofmantleH2O content.Current estimatesfortheH2O contentofthedepletedmantle(50-200ppmwtH2O) areinsufficienttoinduce mantle meltingatthisdepth,whichrequires ∼700 ppmwtH2O toproduce0.1%meltingand1600 ppmwtH2O for1%melting,alonganadiabatwithapotentialtemperatureof1327 ◦C. Meltingcanoccur at theseconditionswithinthemantlesourceofoceanislandbasalts,whichareestimatedtocontainup to900ppmwtH2O. Ifadiabatictemperaturesare200 ◦C higherwithinsuchplumerelatedsources,then melt fractionsofover1%canbereachedat180kmdepth.Inaddition,amodelforthedistributionof H2O betweenperidotitemineralphasesasafunctionofdepthandatH2O-undersaturatedconditions is constructed.Themodelindicatesthatforafixedmantlecompositioncontaining150ppmwtH2O, the olivineH2O contentwillincreasewithdepthsolelyduetochangesininter-phasepartitioningand modal proportionsofminerals.ThechangeintheolivineH2O concentrationwithdepthcorrespondsto proposedchangesinthedominantolivineslipsystemfordeformationbydislocationcreep,thatmight provideanexplanationforthereductioninseismicanisotropyobservedatdepths >200 km

Fluorine and Chlorine in the transition Zone

International audienceWe report concentrations of Fluorine (F) and Chlorine (Cl) in synthetic wadsleyite (Wd) and ringwoodite (Rw). Synthesis were performed under pressures (14–22GPa) and temperatures (1100–1400◦C) relevant to the transition zone (TZ: 410–670 km depth) using multi-anvil press experiments in MLV Clermont-Ferrand, France and in BGI Bayreuth, Germany. F, Cl and Hcontents were measured using Particle Induced Gamma-Ray Emission (PIGE), Particle Induced X-ray Emission (PIXE) and Elastic Recoil Detection Analysis (ERDA) respectively, using a nuclear microprobe at CEA Saclay. Results show that F (up to 850 ppm wt.) and Cl (up to 200 ppm wt.) are concentrated together with H2O in both Wd and Rw (Roberge et al., 2015; 2017).Cl content in Rw and Wd is significantly higher than in other nominally anhydrous minerals of the upper mantle (olivine, pyroxene, garnet), when we found that F is also concentrated in hydrous olivine (up to 1700 ppm wt., Crepisson et al, 2014). With these data we put constraints on the F and Cl budget of the deep Earth, we propose that the TZ may be a major repositoryfor major halogen elements in the mantle. We also show that both F and Cl abundances are underestimated for the bulk silicate Earth (BSE). We propose maximum abundances for the BSE of 59 ppm wt. F and 37 ppm wt. Cl, these abundances are higher than the values proposed by McDonougth and Sun in 1995, of 25 and 17 ppm wt. respectively. New results on F-bearingringwoodite will be presented at the meeting

Herbicide exposure during occupational knapsack spraying in French gardeners and municipal workers

Context: There is a lack of data on pesticide exposure levels during spraying with a knapsack, while it could have important implications for their users’ health. Methods: We assessed levels and determinants of exposure in 24 male private landscapers/gardeners and municipal workers in France in 2011. Actual dermal exposure to glyphosate was assessed with cotton undergarments and gloves, and a cotton coverall changed between mixing and spraying to assess the contribution of each phase and body area to overall contamination. A field monitor observed the whole workshift and filled in a standardized observation grid. Results: The median actual contamination was 5,256 µg for the body, and 4,620 µg for hands. Spraying was more exposing than mixing/loading for all body parts except hands, which contributed to nearly 90% of body exposure during mixing/loading, and 30% during spraying, followed by back (14%). In the most exposed quartile, levels were close to some observations in agriculture. Conclusion: Our study provides new data on pesticide exposure levels of knapsack sprayer users; it should lead to a reinforced prevention, in order to make exposures as low as possible and lessen the risk of chronic diseases

Immunoprofiling of Rice Root Cortex Reveals Two Cortical Subdomains

The formation and differentiation of aerenchyma, i.e., air-containing cavities that are critical for flooding tolerance, take place exclusively in the cortex. The understanding of development and differentiation of the cortex is thus an important issue; however, studies on this tissue are limited, partly because of the lack of available molecular tools. We screened a commercially available library of cell wall antibodies to identify markers of cortical tissue in rice roots. Out of the 174 antibodies screened, eight were cortex-specific. Our analysis revealed that two types of cortical tissues are present in rice root seedlings. We named these cell layers 'inner' and 'outer' based on their location relative to the stele. We then used the antibodies to clarify cell identity in lateral roots. Without these markers, previous studies could not distinguish between the cortex and sclerenchyma in small lateral roots. By immunostaining lateral root sections, we showed that the internal ground tissue in small lateral roots has outer cortical identity

Pesticide Exposure in Fruit-Growers: Comparing Levels and Determinants Assessed under Usual Conditions of Work (CANEPA Study) with Those Predicted by Registration Process (Agricultural Operator Exposure Model)

International audienceKnowledge of pesticide exposure levels in farmers is necessary for epidemiological studies and regulatory purposes. In the European pesticide registration process, operators' exposure is predicted using the Agricultural Operator Exposure Model (AOEM), created in 2014 by the European Food Safety Authority based on studies conducted by the pesticide industry. We compared operators' exposures during treatment days in the apple-growing industry under non-controlled working conditions and AOEM-predicted values. The dermal exposure of thirty French apple-growers from the CANEPA study when applying two fungicides was measured using body patches and cotton gloves. For each observation, the corresponding exposure was calculated by means of the AOEM, using data recorded about the operator, spraying equipment and personal protective equipment (PPE) used. A significant linear correlation was observed between calculated and measured daily exposures. The model overestimated the daily exposure approximately 4-fold and the exposure during application 10-fold. However, exposure was underestimated during mixing/loading for 70% of the observations when the operator wore PPE. The AOEM did not overestimate exposures in all circumstances, especially during mixing/loading, when operators handle concentrated products. The protection provided by PPE appeared to be overestimated. This could be due to the optimal working conditions under which the "industrial" studies are conducted, which may not be representative of real working conditions of operators in fruit-growing