ORCID Profile
0000-0003-3568-605X
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INRAE
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Publisher: Proceedings of the National Academy of Sciences
Date: 21-10-2021
Abstract: The world is witnessing a sharp increase in perennial plant dieback. The hypothesized cause is that environmental stresses such as drought are interacting with pathogens fueling plant decline. Global viticulture has seen similar decreases in fruit yield and vine longevity. One of the hypothesized causes is a synergy between drought and the grapevine vascular disease esca, for which there is no known curative treatment. In sharp contrast to this theory, our study demonstrates that drought completely suppresses esca leaf symptoms, and although esca and drought both alter plant water transport and carbon balance, they do so in completely distinct ways. This understanding reveals the complexity and unpredictability of the stress interactions thought to drive plant mortality.
Publisher: Wiley
Date: 24-09-2020
DOI: 10.1111/PCE.13848
Publisher: Wiley
Date: 23-01-2020
DOI: 10.1111/GEB.13065
Abstract: Large‐scale patterns in flower and fruit traits provide crucial insights into selection processes and the evolutionary history of plant lineages. To isolate and identify the role of selective pressures, including different plant–animal interactions and the factors driving trait evolution, we investigated the convergence and ergence between flower and fruit traits in shared environments. Australia to Southeast Asia. Eocene ( c . 45 Ma) to present. Woody angiosperm rain forest species (2,248 species, 133 families). Using a continental‐scale data set for all woody angiosperm species in the Australian rain forest (1,816 free‐standing and 432 climbing species), we compared the colour and size of fleshy fruits and flowers in relationship to life‐form (trees/shrubs and vines), species biogeographical histories and origins (Sunda versus Sahul) and bioregional distributions. Fleshy fruits in the Australian rain forest are mostly small, with a ersity of colours ( mm 81%), and the flowers are mostly small ( mm 65%) and whitish ( c . 80%). Compared with trees and shrubs, climbing species showed a higher proportion of red fleshy fruits and large coloured flowers. Small whitish flowers were dominant across lineages from different biogeographical origins (Sunda and Sahul) and geographical regions, and both small and large fleshy fruits retained a range of disperser‐attractant colours. Continental‐scale size and colour characteristics of flowers and fleshy fruits differed despite sharing environments with similar abiotic selective pressures through time. Plant–animal interactions, including pollination and dispersal, are likely to mediate different evolutionary outcomes for plant traits and reflect both adaptation and evolutionary constraints.
Publisher: MDPI AG
Date: 10-12-2022
Abstract: Background: While iron deficiency is commonly discussed in populations of professional female athletes, less is known about highly trained, sub-elite female athletes (e.g., those winning international age-group competitions) who generally have less access to medical and allied health support. Methods: Thirteen non-professional highly trained female endurance athletes provided training diaries and completed a blood test, where iron markers of haemoglobin (Hb), haematocrit (Hct), C-reactive protein (Crp), serum iron, serum ferritin, and transferrin were assessed. Resting metabolic rate (RMR) and body composition using dual-energy X-ray absorptiometry (DXA) were also obtained. Participants were classified as iron deficient (ID) if serum ferritin was ug/L serum ferritin. Results: Six of the 13 females were classified as ID. Serum iron, ferritin, Hb, Hct, and ferrin were greater in the ID group (p 0.05). Crp resulted in large to very large correlations with serum iron (r = −0.72), serum ferritin (r = −0.66), and transferrin (r = 0.70). Conclusions: In this population of highly trained female athletes, 46% were diagnosed with sub-optimal iron levels, which could have lasting health effects and impair athletic performance. The need for more education and support in non-professional athletes regarding iron deficiency is strongly advised.
Publisher: Oxford University Press (OUP)
Date: 09-09-2016
DOI: 10.1104/PP.16.01079
Publisher: Cold Spring Harbor Laboratory
Date: 08-09-2020
DOI: 10.1101/2020.09.07.282582
Abstract: Hydraulic failure has been extensively studied during drought-induced plant dieback, but its role in plant-pathogen interactions is under debate. During esca, a grapevine ( Vitis vinifera ) disease, symptomatic leaves are prone to irreversible hydraulic dysfunctions but little is known about the hydraulic integrity of perennial organs over the short- and long-term. We investigated the effects of esca on stem hydraulic integrity in naturally infected plants within a single season and across season(s). We coupled direct ( k s ) and indirect ( k th ) hydraulic conductivity measurements, and tylose and vascular pathogen detection with in vivo X-ray microtomography visualizations. We found xylem occlusions (tyloses), and subsequent loss of stem k s , in all of the shoots with severe symptoms (apoplexy) and in more than 60% of the shoots with moderate symptoms (tiger-stripe), and no tyloses in shoots that were currently asymptomatic. In vivo stem observations demonstrated that tyloses were observed only when leaf symptoms appeared, and resulted in more than 50% PLC in 40% of symptomatic stems, unrelated to symptom age. The impact of esca on xylem integrity was only seasonal and no long-term impact of disease history was recorded. Our study demonstrated how and to what extent a vascular disease such as esca, affecting xylem integrity, could lify plant mortality by hydraulic failure. Our study reveals that esca can critically affect xylem water movement in grapevine perennial organs, by the presence of plant-derived tyloses.
Publisher: Oxford University Press (OUP)
Date: 15-03-0011
Abstract: Xylem anatomy may change in response to environmental or biotic stresses. Vascular occlusion, an anatomical modification of mature xylem, contributes to plant resistance and susceptibility to different stresses. In woody organs, xylem occlusions have been examined as part of the senescence process, but their presence and function in leaves remain obscure. In grapevine, many stresses are associated with premature leaf senescence inducing discolorations and scorched tissue in leaves. However, we still do not know whether the leaf senescence process follows the same sequence of physiological events and whether leaf xylem anatomy is affected in similar ways. In this study, we quantified vascular occlusions in midribs from leaves with symptoms of the grapevine disease esca, magnesium deficiency and autumn senescence. We found higher amounts of vascular occlusions in leaves with esca symptoms (in 27% of xylem vessels on average), whereas the leaves with other symptoms (as well as the asymptomatic controls) had far fewer occlusions (in 3% of vessels). Therefore, we assessed the relationship between xylem occlusions and esca leaf symptoms in four different countries (California in the USA, France, Italy and Spain) and eight different cultivars. We monitored the plants over the course of the growing season, confirming that vascular occlusions do not evolve with symptom age. Finally, we investigated the hydraulic integrity of leaf xylem vessels by optical visualization of embolism propagation during dehydration. We found that the occlusions lead to hydraulic dysfunction mainly in the peripheral veins compared with the midribs in esca symptomatic leaves. These results open new perspectives on the role of vascular occlusions during the leaf senescence process, highlighting the uniqueness of esca leaf symptoms and its consequence on leaf physiology.
Publisher: Elsevier BV
Date: 12-2014
DOI: 10.1016/J.MIMET.2014.10.012
Abstract: Quantitative pathogenicity traits drive the fitness and dynamics of pathogens in agricultural ecosystems and are key determinants of the correct management of crop production over time. However, traits relating to infection potential (i.e. zoospore production) have been less thoroughly investigated in oomycetes than traits relating to dispersal (i.e. sporangium production). We simultaneously quantified sporangium and zoospore production in a biotrophic oomycete, for the joint assessment of life-cycle traits relating to dispersal and infection potentials. We used an automatic particle analyzer to count and size the sporangia and/or zoospores produced at t = 0 min (no zoospore release) and t = 100 min (zoospore release) in 43 Plasmopara viticola isolates growing on the susceptible Vitis vinifera cv. Cabernet Sauvignon. We were able to differentiate and quantify three types of propagules from different stages of the pathogen life cycle: full sporangia, empty sporangia and zoospores. The method was validated by comparing the sporangium and zoospore counts obtained with an automatic particle analyzer and under a stereomicroscope (manual counting). Each isolate produced a mean of 5.8 ± 1.9 (SD) zoospores per sporangium. Significant relationships were found between sporangium production and sporangium size (negative) and between sporangium size and the number of zoospores produced per sporangium (positive). However, there was a significant positive correlation between total sporangium production and total zoospore production. This procedure can provide a valid quantification of the production of both sporangia and zoospores by oomycetes in large numbers of s les, facilitating joint estimation of the dispersal and infection potentials of plant pathogens in various agro-ecological contexts.
Publisher: MDPI AG
Date: 09-07-2019
DOI: 10.3390/NU11071550
Abstract: Personalized hydration strategies play a key role in optimizing the performance and safety of athletes during sporting activities. Clinicians should be aware of the many physiological, behavioral, logistical and psychological issues that determine both the athlete’s fluid needs during sport and his/her opportunity to address them these are often specific to the environment, the event and the in idual athlete. In this paper we address the major considerations for assessing hydration status in athletes and practical solutions to overcome obstacles of a given sport. Based on these solutions, practitioners can better advise athletes to develop practices that optimize hydration for their sports.
Publisher: Informa UK Limited
Date: 24-05-2023
Publisher: Wiley
Date: 18-06-2014
DOI: 10.1111/PLB.12200
Abstract: Plant mating systems are driven by several pre-pollination factors, including pollinator availability, mate availability and reproductive traits. We investigated the relative contributions of these factors to pollination and to realized outcrossing rates in the patchily distributed mass-flowering shrub Rhododendron ferrugineum. We jointly monitored pollen limitation (comparing seed set from intact and pollen-supplemented flowers), reproductive traits (herkogamy, flower size and autofertility) and mating patterns (progeny array analysis) in 28 natural patches varying in the level of pollinator availability (flower visitation rates) and of mate availability (patch floral display estimated as the total number of inflorescences per patch). Our results showed that patch floral display was the strongest determinant of pollination and of the realized outcrossing rates in this mass-flowering species. We found an increase in pollen limitation and in outcrossing rates with increasing patch floral display. Reproductive traits were not significantly related to patch floral display, while autofertility was negatively correlated to outcrossing rates. These findings suggest that mate limitation, arising from high flower visitation rates in small plant patches, resulted in low pollen limitation and high selfing rates, while pollinator limitation, arising from low flower visitation rates in large plant patches, resulted in higher pollen limitation and outcrossing rates. Pollinator-mediated selfing and geitonogamy likely alleviates pollen limitation in the case of reduced mate availability, while reduced pollinator availability (intraspecific competition for pollinator services) may result in the maintenance of high outcrossing rates despite reduced seed production.
Publisher: Wiley
Date: 11-12-2017
Abstract: A ligand field molecular mechanics (LFMM) force field has been constructed for the spin states of [Fe(bpp)
Publisher: American Physiological Society
Date: 08-2007
DOI: 10.1152/JAPPLPHYSIOL.01203.2006
Abstract: This study was conducted during the high-hormone phase of both natural and oral contraceptive pill (OCP)-mediated menstrual cycles to determine whether preexercise ingestion of a concentrated sodium beverage would increase plasma volume (PV), reduce physiological strain, and aid endurance of moderately trained women cycling in warm conditions. Thirteen trained cyclists [peak O 2 uptake 52 ml·kg −1 ·min −1 (SD 2), age 26 yr (SD 6), weight 60.8 kg (SD 5)] who were oral contraceptive users ( n = 6) or not ( n = 7) completed this double-blind, crossover experiment. Cyclists ingested a concentrated-sodium (High Na + : 164 mmol Na + /l) or low-sodium (Low Na + : 10 mmol Na + /l) beverage (10 ml/kg) before cycling to exhaustion at 70% Peak O 2 uptake in warm conditions (32°C, 50% relative humidity, air velocity 4.5 m/s). Beverage (∼628 ml) was ingested in seven portions across 60 min beginning 105 min before exercise, with no additional fluid given until the end of the trial. Trials were separated by one to two menstrual cycles. High Na + increased PV (calculated from hematocrit and hemoglobin concentration) before exercise, whereas Low Na + did not [−4.4 (SD 1.1) vs. −1.9% (SD 1.3) 95% confidence interval: for the difference 5.20, 6.92 P 0.0001], and it involved greater time to exhaustion [98.8 (SD 25.6) vs. 78.7 (SD 24.6) min 95% confidence interval: 13.3, 26.8 P 0.0001]. Core temperature rose more quickly with Low Na + [1.6°C/h (SD 0.2)] than High Na + [1.2°C/h (SD 0.2) P = 0.04]. Plasma [AVP], [Na + ] concentration, and osmolality, and urine volume, [Na + ], and osmolality decreased with sodium loading ( P 0.05) independent of pill usage. Thus preexercise ingestion of a concentrated sodium beverage increased PV, reduced thermoregulatory strain, and increased exercise capacity for women in the high-hormone phase of natural and oral contraceptive pill-mediated menstrual cycles, in warm conditions.
Publisher: Wiley
Date: 21-07-2016
DOI: 10.1002/ECE3.2280
Publisher: Informa UK Limited
Date: 17-09-2019
Publisher: Informa UK Limited
Date: 14-02-2021
Publisher: Springer Science and Business Media LLC
Date: 12-05-2023
DOI: 10.1038/S41598-023-34224-6
Abstract: Maintaining wine production under global warming partly relies on optimizing the choice of plant material for a given viticultural region and developing drought-resistant cultivars. However, progress in these directions is h ered by the lack of understanding of differences in drought resistance among Vitis genotypes. We investigated patterns of xylem embolism vulnerability within and among 30 Vitis species and sub-species (varieties) from different locations and climates, and assessed the risk of drought vulnerability in 329 viticultural regions worldwide. Within a variety, vulnerability to embolism decreased during summer. Among varieties, we have found wide variations in drought resistance of the vascular system in grapevines. This is particularly the case within Vitis vinifera , with varieties distributed across four clusters of embolism vulnerability. Ugni blanc and Chardonnay featured among the most vulnerable, while Pinot noir, Merlot and Cabernet Sauvignon ranked among the most resistant. Regions possibly at greater risk of being vulnerable to drought, such as Poitou–Charentes, France and Marlborough, New Zealand, do not necessarily have arid climates, but rather bear a significant proportion of vulnerable varieties. We demonstrate that grapevine varieties may not respond equally to warmer and drier conditions, and highlight that hydraulic traits are key to improve viticulture suitability under climate change.
Publisher: Human Kinetics
Date: 03-2023
Abstract: Purpose : Although recommendations for effective heat acclimation (HA) strategies for many circumstances exist, best-practice HA protocols specific to elite female team-sport athletes are yet to be established. Therefore, the authors aimed to investigate the effectiveness and retention of a passive HA protocol integrated in a female Olympic rugby sevens team training program. Methods : Twelve elite female rugby sevens athletes undertook 10 days of passive HA across 2 training weeks. Tympanic temperature ( T Tymp ), sweat loss, heart rate, and repeated 6-second cycling sprint performance were assessed using a sport-specific heat stress test Pre-HA, after 3 days (Mid-HA), after 10 days (Post-HA), and 15 days post-HA (Decay). Results : Compared with Pre-HA, submaximal T Tymp was lower Mid-HA and Post-HA (both by −0.2 [0.7] °C d ≥ 0.71), while resting T Tymp was lower Post-HA (by −0.3 [0.2] °C d = 0.81). There were no differences in T Tymp at Decay compared with Pre-HA, nor were there any differences in heart rate or sweat loss at any time points. Mean peak 6-second power output improved Mid-HA and Post-HA (76 [36] W 75 [34] W, respectively d ≥ 0.45) compared with Pre-HA. The observed performance improvement persisted at Decay by 65 (45) W ( d = 0.41). Conclusions : Ten days of passive HA can elicit some thermoregulatory and performance benefits when integrated into a training program in elite female team-sport athletes. However, such a protocol does not provide a sufficient thermal impulse for thermoregulatory adaptations to be retained after 15 days with no further heat stimulus.
Publisher: Wiley
Date: 05-2011
DOI: 10.3732/AJB.1000533
Abstract: Microsatellite primers were developed for Rhododendron ferrugineum (Ericaceae) to evaluate genetic ersity, population genetic structure, and mating system of this self-compatible species. The new-generation 454 FLX Titanium pyrosequencing technology was used to isolate 102 novel microsatellite loci. Two multiplex PCR sets were optimized to genotype nine polymorphic microsatellite loci. The level of genetic ersity was assessed in two populations from the Pyrenees (France). The mean number of alleles per locus ranged from 1.5 to 7. The mean observed and expected heterozygosities ranged from 0 to 0.76 and from 0.03 to 0.66, respectively. Cross-species lification was successful for 13 other Rhododendron species and two additional genera of Ericaceae, with an average of seven pairs of primers lifying per species. These markers will facilitate further studies on the evolutionary history of the large Ericaceae family and Rhododendron in particular.
Publisher: Oxford University Press (OUP)
Date: 15-03-2021
DOI: 10.1093/JXB/ERAB117
Abstract: Hydraulic failure has been extensively studied during drought-induced plant dieback, but its role in plant-pathogen interactions is under debate. During esca, a grapevine (Vitis vinifera) disease, symptomatic leaves are prone to irreversible hydraulic dysfunctions but little is known about the hydraulic integrity of perennial organs over the short- and long-term. We investigated the effects of esca on stem hydraulic integrity in naturally infected plants within a single season and across season(s). We coupled direct (ks) and indirect (kth) hydraulic conductivity measurements, and tylose and vascular pathogen detection with in vivo X-ray microtomography visualizations. Xylem occlusions (tyloses) and subsequent loss of stem hydraulic conductivity (ks) occurred in all shoots with severe symptoms (apoplexy) and in more than 60% of shoots with moderate symptoms (tiger-stripe), with no tyloses in asymptomatic shoots. In vivo stem observations demonstrated that tyloses occurred only when leaf symptoms appeared, and resulted in more than 50% loss of hydraulic conductance in 40% of symptomatic stems, unrelated to symptom age. The impact of esca on xylem integrity was only seasonal, with no long-term impact of disease history. Our study demonstrated how and to what extent a vascular disease such as esca, affecting xylem integrity, could lify plant mortality through hydraulic failure.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-01-2018
Abstract: Long-term observations in Napa Valley and Bordeaux reveal that grapevines never reach a lethal level of drought.
Publisher: Scientific Societies
Date: 12-2022
Publisher: Informa UK Limited
Date: 18-01-2019
Publisher: Wiley
Date: 27-01-2017
DOI: 10.1111/MEC.14006
Abstract: Adaptation produces hard or soft selective sweeps depending on the supply of adaptive genetic polymorphism. The evolution of pesticide resistance in parasites is a striking ex le of rapid adaptation that can shed light on selection processes. Plasmopara viticola, which causes grapevine downy mildew, forms large populations, in which resistance has rapidly evolved due to excessive fungicide use. We investigated the pathways by which fungicide resistance has evolved in this plant pathogen, to determine whether hard or soft selective sweeps were involved. An analysis of nucleotide polymorphism in 108 field isolates from the Bordeaux region revealed recurrent mutations of cytb and CesA3 conferring resistance to quinone outside inhibiting (QoI) and carboxylic acid amide (CAA) fungicides, respectively. Higher levels of genetic differentiation were observed for nucleotide positions involved in resistance than for neutral microsatellites, consistent with local adaptation of the pathogen to fungicide treatments. No hitchhiking was found between selected sites and neighbouring polymorphisms in cytb and CesA3, confirming multiple origins of resistance alleles. We assessed resistance costs, by evaluating the fitness of the 108 isolates through measurements of multiple quantitative pathogenicity traits under controlled conditions. No significant differences were found between sensitive and resistant isolates, suggesting that fitness costs may be absent or negligible. Our results indicate that the rapid evolution of fungicide resistance in P. viticola has involved a soft sweep.
Publisher: Wiley
Date: 20-05-2013
DOI: 10.1111/PLB.12039
Abstract: Fragmentation of natural vegetation creates one of the largest threats to plant-pollinator interactions. Although fragmentation impacts on plant populations have been explored in many, mainly herbaceous, species, the response of wild mass-flowering species is poorly known. Here, we studied 28 heathland patches dominated by the mass-flowering shrub Rhododendron ferrugineum, each presenting different R. ferrugineum floral display sizes (total inflorescence number per patch) and patch isolation (median distance to the three nearest patches). We assessed the impacts of these two factors on (i) heathland patch visitor assemblage (considering R. ferrugineum versus surrounding community) and (ii) R. ferrugineum flower visitation rate and pollen transfer limitation (comparing seed set from emasculated to pollen-supplemented flowers). We found that ersity and abundance of bees visiting R. ferrugineum in heathland patches significantly decreased with decreasing R. ferrugineum floral display, while overall visitor density per patch and flower visitation rate increased. Moreover, a decrease in massive floral display and increase in patch isolation resulted in reduced visitor density in the surrounding community. Even in patches with few in iduals, we found disproportionate visitor abundance in R. ferrugineum compared to the surrounding community. Finally, pollen transfer limitation in R. ferrugineum was neither affected by visitation rate nor by patch attributes. By disproportionally attracting pollinators from co-flowering species, and probably promoting geitonogamous pollen transfer, the mass-flowering trait appears adequate to compensate, in terms of conspecific pollen transfer, for the decrease in visitor ersity and abundance and in mate availability, which usually result from population fragmentation.
Publisher: Oxford University Press (OUP)
Date: 07-06-2016
DOI: 10.1104/PP.16.00829
Abstract: The water transport pipeline in herbs is assumed to be more vulnerable to drought than in trees due to the formation of frequent embolisms (gas bubbles), which could be removed by the occurrence of root pressure, especially in grasses. Here, we studied hydraulic failure in herbaceous angiosperms by measuring the pressure inducing 50% loss of hydraulic conductance (P
Publisher: Wiley
Date: 18-07-2011
Publisher: American Physiological Society
Date: 07-2008
DOI: 10.1152/JAPPLPHYSIOL.01331.2007
Abstract: This study was conducted to investigate effects of an acute sodium load on resting plasma volume (PV) and renal mechanisms across the menstrual cycle of endurance-trained women with natural (NAT) or oral contraceptive pill (OCP) controlled cycles. Twelve women were assigned to one of two groups, according to their usage status: 1) OCP [ n = 6, 29 yr (SD 6), 59.4 kg (SD 3.2)], or 2) NAT [ n = 6, 24 yr (SD 5), 61.3 kg (SD 3.6)]. The sodium load was administered as a concentrated sodium chloride/citrate beverage (164 mmol Na + /l, 253 mosmol/kgH 2 O, 10 ml/kg body mass) during the last high-hormone week of the OCP cycle (OCP high ) or late luteal phase of the NAT cycle (NAT high ) and during the low-hormone sugar pill week of OCP (OCP low ) or early follicular phase of the NAT cycle (NAT low ). The beverage (∼628 ml) was ingested in seven portions across 60 min. Over the next 4 h, PV expanded more in the low-hormone phase for both groups (time-averaged change): OCP low 6.1% (SD 1.1) and NAT low 5.4% (SD 1.2) vs. OCP high 3.9% (SD 0.9) and NAT high 3.5% (SD 0.8) ( P = 0.02). The arginine vasopressin increased less in the low-hormone phase [1.63 (SD 0.2) and 1.30 pg/ml (SD 0.2) vs. 1.82 (SD 0.3) and 1.57 pg/ml (SD 0.5), P = 0.0001], as did plasma aldosterone concentration (∼64% lower, P = 0.0001). Thus PV increased more and renal hormone sensitivity was decreased in the low-hormone menstrual phase following sodium/fluid ingestion, irrespective of OCP usage.
Publisher: Springer Science and Business Media LLC
Date: 04-12-2012
Publisher: Springer Science and Business Media LLC
Date: 30-11-2014
Publisher: Oxford University Press (OUP)
Date: 27-08-2019
DOI: 10.1104/PP.19.00591
Publisher: Wiley
Date: 24-02-2016
DOI: 10.1111/EVA.12368
Publisher: Mary Ann Liebert Inc
Date: 03-2018
Abstract: Mayo, Brad, Cory Miles, Stacy Sims, and Matthew Driller. The effect of resistance training in a hypoxic chamber on physical performance in elite rugby athletes. High Alt Med Biol 19:28-34, 2018.-Limited research suggests that muscle adaptations may be enhanced through resistance training in a hypoxic environment. Seventeen professional rugby union athletes (age [mean ± SD], 24 ± 3 years body mass, 98.7 ± 12.8 kg and height, 188.9 ± 7.9 cm), performed 12 resistance training sessions over a 3-week period. Participants were randomly ided into two groups: HYP (n = 8), where resistance training sessions were performed in an environmental chamber with O
Location: France
No related grants have been discovered for Chloé E.L. Delmas.