Search

Zinc (Zn) shortage is a common micronutrient deficiency affecting plants worldwide, while Zn toxicity may occur when this metal is in excess. Ectomycorrhizal (ECM) fungi are known to be able to modulate the transfer of macro- and microelements, among them Zn, to the plant. However, the underlying mechanisms are not well understood. We identified the HcZnT2 gene from the ECM fungus Hebeloma cylindrosporum , encoding a member of the Cation Diffusion Facilitator (CDF) family including Zn transporters, and analyzed its transcriptional regulation, the transport function by yeast complementation experiments, and its subcellular localization using a GFP fusion protein in yeast. HcZnT2 is highly induced during mycorrhization of Pinus pinaster , and upregulated in presence of the host plant root even without any direct contact. However, HcZnT2 is repressed by Zn excess conditions. By functional expression in yeast, our results strongly support the ability of HcZnT2 to transport Zn and, to a lesser extent, manganese. HcZnT2 localization was associated with the endoplasmic reticulum of yeast. Mycorrhizal gene activation at low external Zn suggests that the Zn transporter HcZnT2 might be important for the early establishment of the ECM symbiosis during Zn deficiency, rather than under Zn excess. HcZnT2 arises as an extremely remarkable candidate playing a key role in Zn homeostasis and regulation in ectomycorrhiza., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Ho-Plágaro, Usman, Swinnen, Ruytinx, Gosti, Gaillard and Zimmermann.)

This article brings together works on the concept of constructed safety in ergonomics, carried out over the last twenty-five years. Firstly, we situate this approach to safety in relation to previously developed existing models previously developed (e.g. regulated and managed safety) with regard to the development of activity-centred ergonomics. We then present six research actions in activity-centred ergonomics from a selection of different fields, from small companies to the industry of the future in an international group: public works, hospitals, aeronautical industry, railway transport, agriculture, and chemical industry, in order to describe constructed safety applications. The results highlight that constructed safety is respectively raised by mutual knowledge between workers and management, collective decision making, collective reflexive work on safety rules, spatiotemporal articulation of the different safety sources, knowledge integration on pesticide exposure situations by designers and regulation, social regulation sustaining risk understanding and safety aspect involving a diversity of actors (workers, preventionists, managers, local residents and public authorities). By focusing on the analysis of actual safety practices in real work and real exposure situations, constructed safety aims to account for the way in which safety is deployed on a daily basis to meet production and health objectives. This understanding contributes to the design of safe work systems in a developmental way and to propose an operating model of constructed safety.

Monitoring pH is one of the challenges in understanding diverse physiological regulations as well as ionic balance, especially in highly acidic environments such as the apoplast and the vacuole. To circumvent the poor efficiency of pH measurements below pH 5, we designed three genetically encoded sensors composed of two fluorescent proteins in tandem. We selected fluorescent protein pairs of low but sufficiently different pKa so that each protein could differentially sense the imposed pH. The generated tandems, named Acidin2, Acidin3, and Acidin4, were produced in Escherichia coli and extensively characterized. Altogether, these generated tandems cover a pH range of 3-8. The Acidins were targeted either for release in the apoplast (Apo) or for anchoring at the outer face of the plasma membrane (PM-Apo), with the fluorescent part exposed in the apoplast. Apoplastic Acidins in stably transformed Arabidopsis thaliana primary roots responded immediately and reversibly to pH changes, directly reporting physiological conditions related to cell elongation. In addition, membrane-anchored Acidins reveal a gradual acidification from the surface through the anticlinal wall of pavement cells, a process controlled at least partially by H+-ATPase activity., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Preeclampsia (PE) is a high-prevalence pregnancy disease characterized by placental insufficiency, gestational hypertension, and proteinuria. Overexpression of the A isoform of the STOX1 transcription factor (STOX1A) recapitulates PE in mice, and STOX1A overexpressing trophoblasts recapitulate PE patients hallmarks in terms of gene expression and pathophysiology. STOX1 overexpression induces nitroso-redox imbalance and mitochondrial hyper-activation. Here, by a thorough analysis on cell models, we show that STOX1 overexpression in trophoblasts alters inducible nitric oxide synthase (iNOS), nitric oxide (NO) content, the nitroso-redox balance, the antioxidant defense, and mitochondrial function. This is accompanied by specific alterations of the Krebs cycle leading to reduced l-malate content. By increasing NOS coupling using the metabolite tetrahydrobiopterin (BH4) we restore this multi-step pathway in vitro. Moving in vivo on two different rodent models (STOX1 mice and RUPP rats, alike early onset and late onset preeclampsia, respectively), we show by transcriptomics that BH4 directly reverts STOX1-deregulated gene expression including glutathione metabolism, oxidative phosphorylation, cholesterol metabolism, inflammation, lipoprotein metabolism and platelet activation, successfully treating placental hypotrophy, gestational hypertension, proteinuria and heart hypertrophy. In the RUPP rats we show that the major fetal issue of preeclampsia, Intra Uterine Growth Restriction (IUGR), is efficiently corrected. Our work posits on solid bases BH4 as a novel potential therapy for preeclampsia., (Published by Elsevier B.V.)

Stomata optimize land plants' photosynthetic requirements and limit water vapor loss. So far, all of the molecular and electrical components identified as regulating stomatal aperture are produced, and operate, directly within the guard cells. However, a completely autonomous function of guard cells is inconsistent with anatomical and biophysical observations hinting at mechanical contributions of epidermal origins. Here, potassium (K+) assays, membrane potential measurements, microindentation, and plasmolysis experiments provide evidence that disruption of the Arabidopsis thaliana K+ channel subunit gene AtKC1 reduces pavement cell turgor, due to decreased K+ accumulation, without affecting guard cell turgor. This results in an impaired back pressure of pavement cells onto guard cells, leading to larger stomatal apertures. Poorly rectifying membrane conductances to K+ were consistently observed in pavement cells. This plasmalemma property is likely to play an essential role in K+ shuttling within the epidermis. Functional complementation reveals that restoration of the wild-type stomatal functioning requires the expression of the transgenic AtKC1 at least in the pavement cells and trichomes. Altogether, the data suggest that AtKC1 activity contributes to the building of the back pressure that pavement cells exert onto guard cells by tuning K+ distribution throughout the leaf epidermis., (© American Society of Plant Biologists 2022. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

The pH parameter of soil plays a key role for plant nutrition as it is affecting the availability of minerals and consequently determines plant growth. Although the mechanisms by which root perceive the external pH is still unknown, the impact of external pH on tissue growth has been widely studied especially in hypocotyl and root. Thanks to technological development of cell imaging and fluorescent sensors, we can now monitor pH in real time with at subcellular definition. In this focus, fluorescent dye-based, as well as genetically-encoded pH indicators are discussed especially with respect to their ability to monitor acidic pH in the context of primary root. The notion of apoplastic subdomains is discussed and suggestions are made to develop fluorescent indicators for pH values below 5.0., (© American Society of Plant Biologists 2021. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Grapevine is one of the most economically important fruit crops due to the high value of its fruit and its importance in winemaking. The current decrease in grape berry quality and production can be seen as the consequence of various abiotic constraints imposed by climate changes. Specifically, produced wines have become too sweet, with a stronger impression of alcohol and fewer aromatic qualities. Potassium is known to play a major role in grapevine growth, as well as grape composition and wine quality. Importantly, potassium ions (K + ) are involved in the initiation and maintenance of the berry loading process during ripening. Moreover, K + has also been implicated in various defense mechanisms against abiotic stress. The first part of this review discusses the main negative consequences of the current climate, how they disturb the quality of grape berries at harvest and thus ultimately compromise the potential to obtain a great wine. In the second part, the essential electrical and osmotic functions of K + , which are intimately dependent on K + transport systems, membrane energization, and cell K + homeostasis, are presented. This knowledge will help to select crops that are better adapted to adverse environmental conditions.

The model legume Medicago truncatula possesses a single outward Shaker K + channel, whereas Arabidopsis thaliana possesses two channels of this type, named AtSKOR and AtGORK, with AtSKOR having been shown to play a major role in K + secretion into the xylem sap in the root vasculature and with AtGORK being shown to mediate the efflux of K + across the guard cell membrane, leading to stomatal closure. Here we show that the expression pattern of the single M. truncatula outward Shaker channel, which has been named MtGORK, includes the root vasculature, guard cells and root hairs. As shown by patch-clamp experiments on root hair protoplasts, besides the Shaker-type slowly activating outwardly rectifying K + conductance encoded by MtGORK, a second K + -permeable conductance, displaying fast activation and weak rectification, can be expressed by M. truncatula. A knock-out (KO) mutation resulting in an absence of MtGORK activity is shown to weakly reduce K + translocation to shoots, and only in plants engaged in rhizobial symbiosis, but to strongly affect the control of stomatal aperture and transpirational water loss. In legumes, the early electrical signaling pathway triggered by Nod-factor perception is known to comprise a short transient depolarization of the root hair plasma membrane. In the absence of the functional expression of MtGORK, the rate of the membrane repolarization is found to be decreased by a factor of approximately two. This defect was without any consequence on infection thread development and nodule production in plants grown in vitro, but a decrease in nodule production was observed in plants grown in soil., (© 2020 The Authors. The Plant Journal © 2020 John Wiley & Sons Ltd.)

STOX1 is a transcription factor involved in preeclampsia and Alzheimer disease. We show that the knock-down of the gene induces rather mild effect on gene expression in trophoblast cell lines (BeWo). We identified binding sites of STOX1 shared by the two major isoforms, STOX1A and STOX1B. Profiling gene expression of cells overexpressing either STOX1A or STOX1B, we identified genes downregulated by both isoforms, with a STOX1 binding site in their promoters. Among those, STOX1-induced Annexin A1 downregulation led to abolished membrane repair in BeWo cells. By contrast, overexpression of STOX1A or B has opposite effects on trophoblast fusion (acceleration and inhibition, respectively) accompanied by syncytin genes deregulation. Also, STOX1A overexpression led to abnormal regulation of oxidative and nitrosative stress. In sum, our work shows that STOX1 isoform imbalance is a cause of gene expression deregulation in the trophoblast, possibly leading to placental dysfunction and preeclampsia., Competing Interests: Declaration of Interests None., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Cerebral palsy (CP) is an umbrella term covering a group of permanent developmental disorders of movement and posture characterized by highly variable clinical features. The aim of this study was to assess the short-term and mid-term effects of neurorehabilitation via hippotherapy on the contractile properties of two key postural muscles during functional sitting in such patients. Thirty-minute hippotherapy sessions were conducted biweekly for 12 weeks in 18 patients (18.1 ± 5.7 years old). Surface electromyography (EMG) was implemented bilaterally in rectus abdominis and adductor magnus. We quantitatively analyzed the amplitude of EMG signals in the time domain and its spectral characteristics in the frequency domain. EMGs were recorded at the beginning and end of each session on day one and at week six and week twelve. Statistical analysis revealed a substantial inter-day reliability of the EMG signals for both muscles, validating the methodological approach. To a lesser extent, while beyond the scope of the current study, quantitative changes suggested a more selective recruitment/contractile properties' shift of the examined muscles. Exploring postural control during functional activities would contribute to understanding the relationship between structural impairment, activity performance and patient capabilities, allowing the design of neurorehabilitation programs aimed at improving postural and functional skills according to each individual's needs. The present study provides basic quantitative data supporting the body of scientific evidence making hippotherapy an approach of choice for CP neurorehabilitation.

Key Message: In a grapevine segregating population, genomic regions governing berry pH were identified, paving the way for breeding new grapevine varieties best adapted to a warming climate. As a consequence of global warming, grapevine berry acidity is expected to dramatically decrease. Adapting grapevine (Vitis vinifera L.) varieties to the climatic conditions of the future requires a better understanding of the genetic architecture of acidity-related traits. For this purpose, we studied during five growing seasons 120 individuals from a grapevine biparental cross. Each offspring was genotyped by simple sequence repeats markers and by hybridization on a 20-K Grapevine Illumina ® SNP chip. Quantitative trait loci (QTLs) for pH colocalized with QTLs for the ratio between potassium and tartaric acid concentrations, on chromosomes 10, 11 and 13. Strong QTLs for malic acid concentration or for the malic acid-to-tartaric acid ratio, on chromosomes 6 and 8, were not associated with variations of pH but can be useful for controlling pH stability under high temperatures. Our study highlights the interdependency between acidity parameters and consequently the constraints and degrees of freedom for designing grapevine genotypes better adapted to the expected warmer climatic conditions. In particular, it is possible to create grapevine genotypes with a high berry acidity as the result of both high tartaric acid concentrations and low K + accumulation capacities.

Potassium (K + ) nutrition is of relevant interest for winegrowers because it influences grapevine growth, berry composition, as well as must and wine quality. Indeed, wine quality strongly depends on berry composition at harvest. However, K + content of grape berries increased steadily over the last decades, in part due to climate change. Currently, the properties and qualities of many fruits are also impacted by environment. In grapevine, this disturbs berry properties resulting in unbalanced wines with poor organoleptic quality and low acidity. This requires a better understanding of the molecular basis of K + accumulation and its control along grape berry development. This mini-review summarizes our current knowledge on K + nutrition in relation with fruit quality in the context of a changing environment., (Copyright © 2020 Villette, Cuéllar, Verdeil, Delrot and Gaillard.)