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Sexual reproduction in flowering plants involves intimate contact and continuous interactions between the growing pollen tube and the female reproductive structures. These interactions can trigger responses in distal regions of the flower well ahead of fertilization. While pollination-induced petal senescence has been studied extensively, less is known about how pollination is perceived at a distance in the ovary, and how specific this response is to various pollen genotypes. To address this question, we performed a global transcriptomic analysis in the ovary of a wild potato species, Solanum chacoense, at various time points following compatible, incompatible, and heterospecific pollinations. In all cases, pollen tube penetration in the stigma was initially perceived as a wounding aggression. Then, as the pollen tubes grew in the style, a growing number of genes became specific to each pollen genotype. Functional classification analyses revealed sharp differences in the response to compatible and heterospecific pollinations. For instance, the former induced reactive oxygen species (ROS)-related genes while the latter affected genes associated to ethylene signaling. In contrast, incompatible pollination remained more akin to a wound response. Our analysis reveals that every pollination type produces a specific molecular signature generating diversified and specific responses at a distance in the ovary in preparation for fertilization.

When plants conquered land, they developed specialized organs, tissues, and cells in order to survive in this new and harsh terrestrial environment. New cell polymers such as the hydrophobic lipid-based polyesters cutin, suberin, and sporopollenin were also developed for protection against water loss, radiation, and other potentially harmful abiotic factors. Cutin and waxes are the main components of the cuticle, which is the waterproof layer covering the epidermis of many aerial organs of land plants. Although the in vivo functions of the group of lipid binding proteins known as lipid transfer proteins (LTPs) are still rather unclear, there is accumulating evidence suggesting a role for LTPs in the transfer and deposition of monomers required for cuticle assembly. In this review, we first present an overview of the data connecting LTPs with cuticle synthesis. Furthermore, we propose liverworts and mosses as attractive model systems for revealing the specific function and activity of LTPs in the biosynthesis and evolution of the plant cuticle.

The fertilization-related kinase 1 (ScFRK1), a nuclear-localized mitogen-activated protein kinase kinase kinase (MAPKKK) from the wild potato species Solanum chacoense, belongs to a small group of pMEKKs that do not possess an extended N- or C-terminal regulatory domain. Initially selected based on its highly specific expression profile following fertilization, in situ expression analyses revealed that the ScFRK1 gene is also expressed early on during female gametophyte development in the integument and megaspore mother cell and, later, in the synergid and egg cells of the embryo sac. ScFRK1 mRNAs are also detected in pollen mother cells. Transgenic plants with lower or barely detectable levels of ScFRK1 mRNAs lead to the production of small fruits with severely reduced seed set, resulting from a concomitant decline in the number of normal embryo sacs produced. Megagametogenesis and microgametogenesis were affected, as megaspores did not progress beyond the functional megaspore (FG1) stage and the microspore collapsed around the first pollen mitosis. As for other mutants that affect embryo sac development, pollen tube guidance was severely affected in the ScFRK1 transgenic lines. Gametophyte to sporophyte communication was also affected, as observed from a marked change in the transcriptomic profiles of the sporophytic tissues of the ovule. The ScFRK1 MAPKKK is thus involved in a signalling cascade that regulates both male and female gamete development.

Solanum chacoense is a wild potato species with superior genetic resistance to diseases and pests that has been extensively used for introgression into cultivated potato. One determinant of crossing success between wild and cultivated potato species is the effective ploidy of the parents. However, little is known about whether other, prezygotic level, breeding barriers exist. We hypothesize ovular pollen tube guidance may serve as such a checkpoint. Tests for species-specific pollen tube guidance using semi-in vivo assays suggested a positive correlation between species-specificity and taxonomic distance. RNA-seq of ovules hand dissected from wild type plants at anthesis and two days before anthesis, as well as from a frk1 mutant lacking an embryo sac identified a list of 284 embryo sac-dependent genes highly expressed in mature ovules and poorly expressed in all other samples. Among these are 17 Solanum chacoense cysteine-rich proteins (ScCRPs), considered to be good candidates since CRPs are ovular pollen tube attractants in other species. A group of three cloned and purified ScCRP2 sequences belonging to the DEFL protein family showed moderate levels of in vitro pollen tube attraction activity in functional assays. We conclude that ScCRP2s are good candidates for ovular pollen tube guidance in S. chacoense. This work introduces key characteristics of pollen tube guidance in Solanum chacoense, identifies candidate attractants through transcriptome subtraction and reports in vitro pollen tube attraction activity for three defensin-like peptides.

In plants, genome stability is maintained during DNA replication by the H3.1K27 methyltransferases ATXR5 and ATXR6, which catalyze the deposition of K27me1 on replication-dependent H3.1 variants. Loss of H3.1K27me1 in atxr5 atxr6 double mutants leads to heterochromatin defects, including transcriptional de-repression and genomic instability, but the molecular mechanisms involved remain largely unknown. In this study, we identified the conserved histone acetyltransferase GCN5 as a mediator of transcriptional de-repression and genomic instability in the absence of H3.1K27me1. GCN5 is part of a SAGA-like complex in plants that requires ADA2b and CHR6 to mediate the heterochromatic defects of atxr5 atxr6 mutants. Our results show that Arabidopsis GCN5 acetylates multiple lysine residues on H3.1 variants in vitro, but that H3.1K27 and H3.1K36 play key roles in inducing genomic instability in the absence of H3.1K27me1. Overall, this work reveals a key molecular role for H3.1K27me1 in maintaining genome stability by restricting histone acetylation in plants. Competing Interest Statement The authors have declared no competing interest.

The optimal perioperative chemotherapy for patients with muscle-invasive bladder cancer is not defined. The VESPER (French Genito-Urinary Tumor Group and French Association of Urology V05) trial reported improved 3-year progression-free survival with dose-dense methotrexate, vinblastine, doxorubicin and cisplatin (dd-MVAC) versus gemcitabine and cisplatin (GC) in patients who received neoadjuvant therapy, but not in the overall perioperative setting. In this Article, we report on the secondary endpoints of overall survival and time to death due to bladder cancer at 5-year follow-up. VESPER was an open-label, randomised, phase 3 trial done at 28 university hospitals or comprehensive cancer centres in France, in which adults (age ≤18 years and ≤80 years) with primary bladder cancer and histologically confirmed muscle-invasive urothelial carcinoma were randomly allocated (1:1; block size four) to treatment with dd-MVAC (every 2 weeks for a total of six cycles) or GC (every 3 weeks for a total of four cycles). Overall survival and time to death due to bladder cancer (presented as 5-year cumulative incidence of death due to bladder cancer) was analysed by intention to treat (ITT) in all randomly assigned patients. Overall survival was assessed by the Kaplan-Meier method with the treatment groups compared with log-rank test stratified for mode of administration of chemotherapy (neoadjuvant or adjuvant) and lymph node involvement. Time to death due to bladder cancer was analysed with an Aalen model for competing risks and a Fine and Gray regression model stratified for the same two covariates. Results were presented for the total perioperative population and for the neoadjuvant and adjuvant subgroups. The trial is registered with ClinicalTrials.gov, NCT01812369, and is complete. From Feb 25, 2013, to March 1, 2018, 500 patients were randomly assigned, of whom 493 were included in the final ITT population (245 [50%] in the GC group and 248 [50%] in the dd-MVAC group; 408 [83%] male and 85 [17%] female). 437 (89%) patients received neoadjuvant chemotherapy. Median follow-up was 5·3 years (IQR 5·1–5·4); 190 deaths at the 5-year cutoff were reported. In the perioperative setting (total ITT population), we found no evidence of association of overall survival at 5 years with dd-MVAC treatment versus GC treatment (64% [95% CI 58–70] vs 56% [50–63], stratified hazard ratio [HRstrat] 0·79 [95% CI 0·59–1·05]). Time to death due to bladder cancer was increased in the dd-MVAC group compared with in the GC group (5-year cumulative incidence of death: 27% [95% CI 21–32] vs 40% [34–46], HRstrat 0·61 [95% CI 0·45–0·84]). In the neoadjuvant subgroup, overall survival at 5 years was improved in the dd-MVAC group versus the GC group (66% [95% CI 60–73] vs 57% [50–64], HR 0·71 [95% CI 0·52–0·97]), as was time to death due to bladder cancer (5-year cumulative incidence: 24% [18–30] vs 38% [32–45], HR 0·55 [0·39–0·78]). In the adjuvant subgroup, the results were not conclusive due to the small sample size. Bladder cancer progression was the cause of death for 157 (83%) of the 190 deaths; other causes of death included cardiovascular events (eight [4%] deaths), deaths related to chemotherapy toxicity (four [2%]), and secondary cancers (four [2%]). Our results on overall survival at 5 years were in accordance with the primary endpoint analysis (3-year progression-free survival). We found no evidence of improved overall survival with dd-MVAC over GC in the perioperative setting, but the data support the use of six cycles of dd-MVAC over four cycles of GC in the neoadjuvant setting. These results should impact practice and future trials of immunotherapy in bladder cancer. French National Cancer Institute.

The concept of a single-input/multi-output thermal network was proposed by the Development of Libraries of Physical models for an Integrated design environment (DELPHI) consortium more than twenty years ago. The present work highlights the recent improvements made to efficiently derive a low-computing-effort model from a fully detailed numerical model and to characterize its performances. The temperature predictions of a deduced ball-grid-array (BGA) dynamic compact thermal model are compared to those of a realistic three-dimensional representation, including the large set of internal copper traces, as well as its board structure, which has been validated by experiment. The current study discloses a method for creating an amalgam reduced-order modal model (AROMM) for that electronic component family that allows the preservation of the geometry integrity and shortening scenarios computation. Typically, the AROMM method reduces by a factor of 600 the computation time needed to obtain the solution while keeping the error on the maximum temperature below 2%. Then, a meta-heuristic optimization is run to derive a more practical low-order resistor capacitor model that enables a thermo-fluidic analysis at the board level. Based on the calibrated numerical model, a novel AROMM method was investigated in order to address the chip behavior submitted to multiple heat sources. The first results highlight the capability to enforce a non-uniform power distribution on the upper surface of the silicon chip. Thus, the chip design layout can be analyzed and optimized to prevent thermal and reliability issues.

This work deals with Perfectly Matched Layers (PMLs) in the context of dispersive media, and in particular for Negative Index Metamaterials (NIMs). We first present some properties of dispersive isotropic Maxwell equations that include NIMs. We propose and analyse the stability of very general PMLs for a large class of dispersive systems using a new change of variable. We give necessary criteria for the stability of such models that show in particular that the classical PMLs applied to NIMs are unstable and we confirm this numerically. For dispersive isotropic Maxwell equations, this analysis is completed by giving necessary and sufficient conditions of stability. Finally, we propose new PMLs that satisfy these criteria and demonstrate numerically their efficiency.

We present here the results obtained during an intensive field campaign conducted in the framework of the French “BIO-MAÏDO” (Bio-physico-chemistry of tropical clouds at Maïdo (Réunion Island): processes and impacts on secondary organic aerosols' formation) project. This study integrates an exhaustive chemical and microphysical characterization of cloud water obtained in March–April 2019 in Réunion (Indian Ocean). Fourteen cloud samples have been collected along the slope of this mountainous island. Comprehensive chemical characterization of these samples is performed, including inorganic ions, metals, oxidants, and organic matter (organic acids, sugars, amino acids, carbonyls, and low-solubility volatile organic compounds, VOCs). Cloud water presents high molecular complexity with elevated water-soluble organic matter content partly modulated by microphysical cloud properties. As expected, our findings show the presence of compounds of marine origin in cloud water samples (e.g. chloride, sodium) demonstrating ocean–cloud exchanges. Indeed, Na+ and Cl− dominate the inorganic composition contributing to 30 % and 27 %, respectively, to the average total ion content. The strong correlations between these species (r2 = 0.87, p value: < 0.0001) suggest similar air mass origins. However, the average molar Cl-/Na+ ratio (0.85) is lower than the sea-salt one, reflecting a chloride depletion possibly associated with strong acids such as HNO3 and H2SO4. Additionally, the non-sea-salt fraction of sulfate varies between 38 % and 91 %, indicating the presence of other sources. Also, the presence of amino acids and for the first time in cloud waters of sugars clearly indicates that biological activities contribute to the cloud water chemical composition. A significant variability between events is observed in the dissolved organic content (25.5 ± 18.4 mg C L−1), with levels reaching up to 62 mg C L−1. This variability was not similar for all the measured compounds, suggesting the presence of dissimilar emission sources or production mechanisms. For that, a statistical analysis is performed based on back-trajectory calculations using the CAT (Computing Atmospheric Trajectory Tool) model associated with the land cover registry. These investigations reveal that air mass origins and microphysical variables do not fully explain the variability observed in cloud chemical composition, highlighting the complexity of emission sources, multiphasic transfer, and chemical processing in clouds. Even though a minor contribution of VOCs (oxygenated and low-solubility VOCs) to the total dissolved organic carbon (DOC) (0.62 % and 0.06 %, respectively) has been observed, significant levels of biogenic VOC (20 to 180 nmol L−1) were detected in the aqueous phase, indicating the cloud-terrestrial vegetation exchange. Cloud scavenging of VOCs is assessed by measurements obtained in both the gas and aqueous phases and deduced experimental gas-/aqueous-phase partitioning was compared with Henry's law equilibrium to evaluate potential supersaturation or unsaturation conditions. The evaluation reveals the supersaturation of low-solubility VOCs from both natural and anthropogenic sources. Our results depict even higher supersaturation of terpenoids, evidencing a deviation from thermodynamically expected partitioning in the aqueous-phase chemistry in this highly impacted tropical area.