Identification of salicylic acid-independent responses in an Arabidopsis 3 phosphatidylinositol 4-kinase beta double mutant

International audienceBackground and AimsWe have recently shown that an Arabidopsis thaliana double mutant of type III phosphatidylinositol-4-kinases (PI4Ks), pi4kβ1β2, constitutively accumulated a high level of salicylic acid (SA). By crossing this pi4kβ1β2 double mutant with mutants impaired in SA synthesis (such as sid2 impaired in isochorismate synthase) or transduction, we demonstrated that the high SA level was responsible for the dwarfism phenotype of the double mutant. Here we aimed at distinguishing between the SA-dependent and -independent effects triggered by the deficiency in PI4Kβ1 and PI4Kβ2.MethodsTo achieve this, the sid2pi4kβ1β2 triple mutant was a tool of choice. High-throughput analyses of phytohormones were performed on this mutant together with pi4kβ1β2 and sid2 mutants and wild-type plants. Responses to pathogens, namely Hyaloperonospora arabidopsidis, Pseudomonas syringae and Botrytis cinerea, but as well to the non-host fungus Blumeria graminis, were also determined. Callose accumulation was monitored in response to flagellin. Key ResultsWe show here the prominent role of high SA levels in influencing the concentration of many other tested phytohormones, including abscisic acid and its derivatives, the Aspartate-conjugated form of indole-3-acetic acid and some cytokinins such as cis-zeatin. We show that the increased resistance of pi4kβ1β2 plants to the host pathogens Hyaloperonospora arabidopsidis, Pseudomonas syringae pv. tomato DC3000 and Bothrytis cinerea is dependent on accumulation of high SA level. In contrast, accumulation of callose in pi4kβ1β2 after flagellin treatment was independent of SA. Concerning the response to Blumeria graminis, both callose accumulation and fungal penetration were enhanced in the pi4kβ1β2 double mutant compared to wild-type plants. Both of these processes occurred in a SA-independent manner. ConclusionsOur data extensively illustrate the influence of SA on other phytohormone levels. The sid2pi4kβ1β2 triple mutant allowed to uncover the role of PI4Kβ1/β2 per se, thus showing the importance of these enzymes in plant defence responses

Individualized versus conventional ovarian stimulation for in vitro fertilization: a multicenter, randomized, controlled, assessor-blinded, phase 3 noninferiority trial

Objective To compare the efficacy and safety of follitropin delta, a new human recombinant FSH with individualized dosing based on serum antimüllerian hormone (AMH) and body weight, with conventional follitropin alfa dosing for ovarian stimulation in women undergoing IVF. Design Randomized, multicenter, assessor-blinded, noninferiority trial (ESTHER-1). Setting Reproductive medicine clinics. Patient(s) A total of 1,329 women (aged 18â40 years). Intervention(s) Follitropin delta (AMH <15 pmol/L: 12 μg/d; AMH â¥15 pmol/L: 0.10â0.19 μg/kg/d; maximum 12 μg/d), or follitropin alfa (150 IU/d for 5 days, potential subsequent dose adjustments; maximum 450 IU/d). Main Outcomes Measure(s) Ongoing pregnancy and ongoing implantation rates; noninferiority margins â8.0%. Result(s) Ongoing pregnancy (30.7% vs. 31.6%; difference â0.9% [95% confidence interval (CI) â5.9% to 4.1%]), ongoing implantation (35.2% vs. 35.8%; â0.6% [95% CI â6.1% to 4.8%]), and live birth (29.8% vs. 30.7%; â0.9% [95% CI â5.8% to 4.0%]) rates were similar for individualized follitropin delta and conventional follitropin alfa. Individualized follitropin delta resulted in more women with target response (8â14 oocytes) (43.3% vs. 38.4%), fewer poor responses (fewer than four oocytes in patients with AMH <15 pmol/L) (11.8% vs. 17.9%), fewer excessive responses (â¥15 or â¥20 oocytes in patients with AMH â¥15 pmol/L) (27.9% vs. 35.1% and 10.1% vs. 15.6%, respectively), and fewer measures taken to prevent ovarian hyperstimulation syndrome (2.3% vs. 4.5%), despite similar oocyte yield (10.0 ± 5.6 vs. 10.4 ± 6.5) and similar blastocyst numbers (3.3 ± 2.8 vs. 3.5 ± 3.2), and less gonadotropin use (90.0 ± 25.3 vs. 103.7 ± 33.6 μg). Conclusion(s) Optimizing ovarian response in IVF by individualized dosing according to pretreatment patient characteristics results in similar efficacy and improved safety compared with conventional ovarian stimulation. Clinical Trial Registration Number NCT01956110

Birthweight difference of singletons conceived through in vitro fertilization with frozen versus fresh embryo transfer: An analysis of 5406 embryo transfers in a retrospective study 2013-2018

International audienceINTRODUCTION: Perinatal risks after frozen embro transfer (FET) have been reassuring but some authors suggest that birthweights are higher after FET than after fresh embryo transfer (ET). The primary objective of this retrospective study, conducted in Clinique de la Sagesse, Rennes (France) from December 2013 to March 2017, was to determine whether a difference in birthweight exists between children conceived through in vitro fertilization (IVF) with frozen versus fresh ET. The secondary objective was to compare live birth rates after frozen versus fresh cycles.MATERIAL AND METHODS: All couples undergoing IVF were included. Cycles with gamete donation and twin pregnancies were excluded. Hormone therapy was used in all embryo transfers. The main outcome measures were the child's birthweight, mode of delivery, gestation length and sex, maternal characteristics, and IVF characteristics. The primary endpoint was birthweight.RESULTS: We studied 5406 embryo transfers and the 708 resulting singleton live births on which birthweight data were available. Mean birthweight was 3357g after frozen embryo transfer versus 3183g after fresh embryo transfer (p<0.001). After adjusting for confounding factors, the children born after frozen embryo transfer were 165.2g heavier (95%CI [92.96-237.51]). No difference was found in gestation length. Live birth was obtained after the 1.6th IVF attempt. Live birth rate was higher for fresh cycles (19% versus 12%, p<0.001), and the caesarean rate lower (16% versus 21%).DISCUSSION: Birthweight was higher after frozen embryo transfer for a similar gestational age. Further research is needed to elucidate the mechanisms responsible for this difference

Les communautés virtuelles de santé contribuentelles à façonner la relation patient-médecin ?

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Spécificité tissulaire de l'expression du gène rolA dans des tabacs transgéniques et compartimentation de la protéine rolA

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Arabidopsis A BOUT DE SOUFFLE is a putative mitochondrial transporter involved in photorespiratory metabolism and is required for meristem growth at ambient CO levels

Eisenhut M, Planchais S, Cabassa C, et al. Arabidopsis A BOUT DE SOUFFLE is a putative mitochondrial transporter involved in photorespiratory metabolism and is required for meristem growth at ambient CO levels. Plant Journal, The . 2013;73(5):836-849.Photorespiratory metabolism is essential in all oxygenic photosynthetic organisms. In plants, it is a highly compartmentalized pathway that involves chloroplasts, peroxisomes, mitochondria and the cytoplasm. The metabolic pathway itself is well characterized, and the enzymes required for its function have been identified. However, very little information is available on the transport proteins that catalyze the high metabolic flux between the involved compartments. Here we show that the A BOUT DE SOUFFLE (BOU) gene, which encodes a mitochondrial carrier, is involved in photorespiration in Arabidopsis. BOU was found to be co-expressed with photorespiratory genes in leaf tissues. The knockout mutant bou-2 showed the hallmarks of a photorespiratory growth phenotype, an elevated CO2 compensation point, and excessive accumulation of glycine. Furthermore, degradation of the P-protein, a subunit of glycine decarboxylase, was demonstrated for bou-2, and is reflected in strongly reduced glycine decarboxylase activity. The photorespiration defect in bou-2 has dramatic consequences early in the seedling stage, which are highlighted by transcriptome studies. In bou-2 seedlings, as in shm1, another photorespiratory mutant, the shoot apical meristem organization is severely compromised. Cell divisions are arrested, leading to growth arrest at ambient CO2. Although the specific substrate for the BOU transporter protein remains elusive, we show that it is essential for the function of the photorespiratory metabolism. We hypothesize that BOU function is linked with glycine decarboxylase activity, and is required for normal apical meristems functioning in seedlings