Two chemically distinct root lignin barriers control solute and water balance.

Lignin is a complex polymer deposited in the cell wall of specialised plant cells, where it provides essential cellular functions. Plants coordinate timing, location, abundance and composition of lignin deposition in response to endogenous and exogenous cues. In roots, a fine band of lignin, the Casparian strip encircles endodermal cells. This forms an extracellular barrier to solutes and water and plays a critical role in maintaining nutrient homeostasis. A signalling pathway senses the integrity of this diffusion barrier and can induce over-lignification to compensate for barrier defects. Here, we report that activation of this endodermal sensing mechanism triggers a transcriptional reprogramming strongly inducing the phenylpropanoid pathway and immune signaling. This leads to deposition of compensatory lignin that is chemically distinct from Casparian strip lignin. We also report that a complete loss of endodermal lignification drastically impacts mineral nutrients homeostasis and plant growth

Coordination between microbiota and root endodermis supports plant mineral nutrient homeostasis

Plant roots and animal guts have evolved specialized cell layers to control mineral nutrient homeostasis. These layers must tolerate the resident microbiota while keeping homeostatic integrity. Whether and how the root diffusion barriers in the endodermis, which are critical for the mineral nutrient balance of plants, coordinate with the microbiota is unknown. We demonstrate that genes controlling endodermal function in the model plant Arabidopsis thaliana contribute to the plant microbiome assembly. We characterized a regulatory mechanism of endodermal differentiation driven by the microbiota with profound effects on nutrient homeostasis. Furthermore, we demonstrate that this mechanism is linked to the microbiota's capacity to repress responses to the phytohormone abscisic acid in the root. Our findings establish the endodermis as a regulatory hub coordinating microbiota assembly and homeostatic mechanisms

A novel signaling pathway required for Arabidopsis endodermal root organization shapes the Rhizosphere microbiome

The Casparian strip (CS) constitutes a physical diffusion barrier to water and nutrients in plant roots, which is formed by the polar deposition of lignin polymer in the endodermis tissue. The precise pattern of lignin deposition is determined by the scaffolding activity of membrane-bound Casparian Strip domain proteins (CASPs), but little is known of the mechanism(s) directing this process. Here, we demonstrate that Endodermis-specific Receptor-like Kinase 1 (ERK1) and, to a lesser extent, ROP Binding Kinase1 (RBK1) are also involved in regulating CS formation, with the former playing an essential role in lignin deposition as well as in the localization of CASP1. We show that ERK1 is localized to the cytoplasm and nucleus of the endodermis and that together with the circadian clock regulator, Time for Coffee (TIC), forms part of a novel signaling pathway necessary for correct CS organization and suberization of the endodermis, with their single or combined loss of function resulting in altered root microbiome composition. In addition, we found that other mutants displaying defects in suberin deposition at the CS also display altered root exudates and microbiome composition. Thus, our work reveals a complex network of signaling factors operating within the root endodermis that establish both the CS diffusion barrier and influence the microbial composition of the rhizosphere

Same data, different conclusions: Radical dispersion in empirical results when independent analysts operationalize and test the same hypothesis

In this crowdsourced initiative, independent analysts used the same dataset to test two hypotheses regarding the effects of scientists’ gender and professional status on verbosity during group meetings. Not only the analytic approach but also the operationalizations of key variables were left unconstrained and up to individual analysts. For instance, analysts could choose to operationalize status as job title, institutional ranking, citation counts, or some combination. To maximize transparency regarding the process by which analytic choices are made, the analysts used a platform we developed called DataExplained to justify both preferred and rejected analytic paths in real time. Analyses lacking sufficient detail, reproducible code, or with statistical errors were excluded, resulting in 29 analyses in the final sample. Researchers reported radically different analyses and dispersed empirical outcomes, in a number of cases obtaining significant effects in opposite directions for the same research question. A Boba multiverse analysis demonstrates that decisions about how to operationalize variables explain variability in outcomes above and beyond statistical choices (e.g., covariates). Subjective researcher decisions play a critical role in driving the reported empirical results, underscoring the need for open data, systematic robustness checks, and transparency regarding both analytic paths taken and not taken. Implications for organizations and leaders, whose decision making relies in part on scientific findings, consulting reports, and internal analyses by data scientists, are discussed

Sténoses trachéales de l'adulte

National audienceLes sténoses trachéales sont situées au carrefour de la laryngologie, de la pneumologie, de l'imagerie, de l'endoscopie, de la chirurgie cervicothoracique et de la réanimation. Ces sténoses peuvent être congénitales ou acquises. La sténose peut être laryngotrachéale, cervicale et/ou thoracique. Les causes des sténoses trachéales sont nombreuses, mais largement dominées par les traumatismes liés aux différents modes d'assistance respiratoire. Si d'un point de vue étiologique, clinique, diagnostique, les données sont bien définies dans la littérature, il n'en est pas de même du traitement chirurgical qui reste encore mal codifié. Le traitement peut être fait par voie externe. Il peut être également endoscopique. Actuellement, les progrès de l'endoscopie interventionnelle trachéale amènent des éléments nouveaux dans la stratégie de traitement des sténoses trachéales de l'adulte, notamment chez les sujets les plus fragiles. Chez un même patient, le traitement peut faire appel à différentes techniques en fonction de la localisation, du type de sténose, de l'âge, de l'état général et de l'évolution dans le temps de certains de ces éléments. Une prise en charge pluridisciplinaire est donc nécessaire