Abnormal segregations in crosses between two cultivated rice species

International audienc

Differential responses of Brassica oleracea and B. rapa accessions to seven isolates of Peronospora parasitica at the cotyledon stage

Nineteen accessions of Brassica oleracea var. italica (broccoli), 31 of B. oleracea var. boirytis (cauliflower), two of B. oleracea var. capitata (cabbage), three of B. rapa subsp, rapifera (turnip), one of B. rapa subsp, pekinensis (Chinese cabbage), and three of Raphanus sativus (radish) were tested for their response to isolates of Peronospora parasitica (downy mildew) at the cotyledon stage. Of the seven isolates tested, four were from crops of cauliflower in France, two from oilseed rape (B. napus subsp, oleifera) in the UK, and one was from mustard (B. juncea) in India. Twenty-one differential responses to P. parasitica isolates from B. oleracea and two from B. rapa were identified. All Raphanus sativus accessions were resistant to all seven isolates. Accessions for which seedling populations exhibited a heterogeneous reaction to some isolates were classified in a separate category. The differential resistance to P. parasitica identified in B. oleracea and B. rapa can be used for future studies of the genetics of the host-pathogen interaction and for breeding for disease resistanc

In vitro seeds germination and seedling growth of cashew (Anacardium occidentale L.)

In Côte d’Ivoire, the yield of cashew nuts is low. This situation has led to the use of improved clonal-based material for the expansion or establishment of new plantations. To obtain a mass propagation of such elite materials, application of tissue culture becomes very important. However, it is difficult to obtain viable explants derived from mature plants developing in field because of high concentrations of disinfectants required for surface sterilization. Explants excised from in vitro seedlings are therefore the most suitable for the micropropagation of cashew. The objective of this study was to identify the type of seeds suitable for in vitro germination and plantlets development. Seeds without shell with entire cotyledons (SWSEC), seeds without shells with half cotyledons (SWSHC) and the embryonic axis (EA) were placed on the basal medium of Murashige and Skoog (MS) without any plant growth regulators. The final rate of germination ranged from 75 to 95 %, the time to have 50 % germination and the average germination time were statistically identical with the three types of seeds. Higher plants (7cm) with larger numbers of leaves, which are more vigorous were obtained with SWSHC. This type of seeds is therefore more suitable provide seedling used as explant sources for themicropropagation of the cashew tree.Key words : Anacardium occidentale ; germination ; micropropagatio

Targeted Cyclo[8]pyrrole-Based NIR-II Photoacoustic Tomography Probe for Suppression of Orthotopic Pancreatic Tumor Growth and Intra-abdominal Metastases

Pancreatic cancer is highly lethal. New diagnostic and treatment modalities are desperately needed. We report here that an expanded porphyrin, cyclo[8]pyrrole (CP), with a high extinction coefficient (89.16 L/g·cm) within the second near-infrared window (NIR-II), may be formulated with an αvβ3-specific targeting peptide, cyclic-Arg-Gly-Asp (cRGD), to form cRGD-CP nanoparticles (cRGD-CPNPs) with promising NIR-II photothermal (PT) therapeutic and photoacoustic (PA) imaging properties. Studies with a ring-array PA tomography system, coupled with analysis of control nanoparticles lacking a targeting element (CPNPs), revealed that cRGD conjugation promoted the delivery of the NPs through abnormal vessels around the tumor to the solid tumor core. This proved true in both subcutaneous and orthotopic pancreatic tumor mice models, as confirmed by immunofluorescent studies. In combination with NIR-II laser photoirradiation, the cRGD-CPNPs provided near-baseline tumor growth inhibition through PTT both in vitro and in vivo. Notably, the combination of the present cRGD-CPNPs and photoirradiation was found to inhibit intra-abdominal metastases in an orthotopic pancreatic tumor mouse model. The cRGD-CPNPs also displayed good biosafety profiles, as inferred from PA tomography, blood analyses, and H&E staining. They thus appear promising for use in combined PA imaging and PT therapeutic treatment of pancreatic cancer

Limited efficacy of repeated praziquantel treatment in Schistosoma mansoni infections as revealed by highly accurate diagnostics, PCR and UCP-LF CAA (RePST trial)

BACKGROUND: Most studies assessing praziquantel (PZQ) efficacy have used relatively insensitive diagnostic methods, thereby overestimating cure rate (CR) and intensity reduction rate (IRR). To determine accurately PZQ efficacy, we employed more sensitive DNA and circulating antigen detection methods. METHODOLOGY: A sub-analysis was performed based on a previously published trial conducted in children from Cote d'Ivoire with a confirmed Schistosoma mansoni infection, who were randomly assigned to a standard (single dose of PZQ) or intense treatment group (4 repeated doses of PZQ at 2-week intervals). CR and IRR were estimated based on PCR detecting DNA in a single stool sample and the up-converting particle lateral flow (UCP-LF) test detecting circulating anodic antigen (CAA) in a single urine sample, and compared with traditional Kato-Katz (KK) and point-of-care circulating cathodic antigen (POC-CCA). PRINCIPAL FINDINGS: Individuals positive by all diagnostic methods (i.e., KK, POC-CCA, PCR, and UCP-LF CAA) at baseline were included in the statistical analysis (n = 125). PCR showed a CR of 45% (95% confidence interval (CI) 32-59%) in the standard and 78% (95% CI 66-87%) in the intense treatment group, which is lower compared to the KK results (64%, 95% CI 52-75%) and 88%, 95% CI 78-93%). UCP-LF CAA showed a significantly lower CR in both groups, 16% (95% CI 11-24%) and 18% (95% CI 12-26%), even lower than observed by POC-CCA (31%, 95% CI 17-35% and 36%, 95% CI 26-47%). A substantial reduction in DNA and CAA-levels was observed after the first treatment, with no further decrease after additional treatment and no significant difference in IRR between treatment groups. CONCLUSION/SIGNIFICANCE: The efficacy of (repeated) PZQ treatment was overestimated when using egg-based diagnostics. Quantitative worm-based diagnostics revealed that active Schistosoma infections are still present despite multiple treatments. These results stress the need for using accurate diagnostic tools to monitor different PZQ treatment strategies, in particular when moving toward elimination of schistosomiasis. CLINICAL TRIAL REGISTRATION: www.clinicaltrials.gov, NCT02868385

Multiple Translocation of the AVR-Pita Effector Gene among Chromosomes of the Rice Blast Fungus Magnaporthe oryzae and Related Species

Magnaporthe oryzae is the causal agent of rice blast disease, a devastating problem worldwide. This fungus has caused breakdown of resistance conferred by newly developed commercial cultivars. To address how the rice blast fungus adapts itself to new resistance genes so quickly, we examined chromosomal locations of AVR-Pita, a subtelomeric gene family corresponding to the Pita resistance gene, in various isolates of M. oryzae (including wheat and millet pathogens) and its related species. We found that AVR-Pita (AVR-Pita1 and AVR-Pita2) is highly variable in its genome location, occurring in chromosomes 1, 3, 4, 5, 6, 7, and supernumerary chromosomes, particularly in rice-infecting isolates. When expressed in M. oryzae, most of the AVR-Pita homologs could elicit Pita-mediated resistance, even those from non-rice isolates. AVR-Pita was flanked by a retrotransposon, which presumably contributed to its multiple translocation across the genome. On the other hand, family member AVR-Pita3, which lacks avirulence activity, was stably located on chromosome 7 in a vast majority of isolates. These results suggest that the diversification in genome location of AVR-Pita in the rice isolates is a consequence of recognition by Pita in rice. We propose a model that the multiple translocation of AVR-Pita may be associated with its frequent loss and recovery mediated by its transfer among individuals in asexual populations. This model implies that the high mobility of AVR-Pita is a key mechanism accounting for the rapid adaptation toward Pita. Dynamic adaptation of some fungal plant pathogens may be achieved by deletion and recovery of avirulence genes using a population as a unit of adaptation

Stocks de carbone dans des sols sous agriculture familiale en Afrique Sub-Saharienne – les enseignements du projet SoCa

Une augmentation infime des quantités de carbone organique présent dans les 30 à 40 premiers centimètres des sols permettrait de contrebalancer les quantités de CO2 rejetées annuellement dans l'atmosphère par les activités anthropiques (https://www.4p1000.org/fr), avec des co-bénéfices en termes de fertilité des sols et de productivité agricole. Toutefois, le stockage du carbone dans le sol dépend de nombreux facteurs dont le climat, le type de sol, son occupation et les pratiques agricoles. Autant de facteurs peu étudiés, notamment dans les systèmes agricoles familiaux des zones tropicales, alors même que les enjeux sont là plus importants qu'ailleurs. Le projet Beyond climate, Soil Carbon sequestration to sustain tropical family farming " SoCa " s'est intéressé au Carbone des sols pour l'agriculture familiale en zone tropicale. Ce projet est né des collaborations tissées entre chercheurs africains, malgaches, et français au sein du réseau CaSA Carbone des Sols pour une Agriculture durable en Afrique. Il répond aux enjeux de l'atténuation et de l'adaptation aux changements climatiques (ODD 13), de la sécurité alimentaire (ODD 2), mais aussi dans une moins mesure à la préservation de la biodiversité (ODD 15). Conduit entre 2017 et 2023 dans 4 pays d'Afrique (Bénin, Cameroun, Côte d'Ivoire, Sénégal) et à Madagascar, SoCa a permis de soutenir les activités de recherche de 3 post-doctorants et 8 doctorants. Le projet a examiné des situations pédoclimatiques et culturales variées, notamment des systèmes de cultures annuelles sous parc à Faidherbia en zone aride, des systèmes agroforestiers complexes sous climat tropical plus humide, et la riziculture pluviale d'altitude. Tous les systèmes de culture étudiés ont été choisis en situation de bas intrants, contexte particulier de l'Agriculture familiale dans les pays du Sud. La collecte de données socio-économiques et biophysiques sur ces terrains d'étude a permis la quantification des stocks de Carbone sous différents systèmes et la compréhension des processus impliqués aux échelles locales, afin d'appuyer les agriculteurs dans leurs pratiques agroécologiques. Une sélection des principaux produits du projet (base de données ; cartes ; publications scientifiques ; bande dessinée ; vidéo ;…) sera présentée, accompagnée des messages clés

Increase of tuberculosis incidence in Ile-de-France region and the role of recent migration

Abstract Background In metropolitan France and in the Ile-de-France region, the incidence of tuberculosis has globally decreased since the year 2000 and has stabilized from 2011 to 2015. This study analysed the evolution of tuberculosis in the Ile-de-France region between 2015 and 2017. Methods We analysed tuberculosis cases reported in Ile-de-France from 2015 to 2017; 2015 was considered as the baseline year. Incidence rates of reported tuberculosis cases were estimated using French census data for the corresponding year for the denominator. Age-standardized rates were estimated for each of the 8 departments of the region based on the Ile-de-France region population. Foreigners’ population was based on the 2015 French census data. Differences in incidence and proportions were tested with the CHI2 statistic (STATA® v14.0). Results The incidence of tuberculosis increased in the Ile-de-France region from 14.6 to 15.8/100 000 pop. between 2015 and 2017 (+8.2%, p &amp;lt; 0.01). In this region, all department’s incidence were above 10/100 000 pop. in 2017. Sub-regional disparities were observed, with an important increase of the incidence in Paris, from 13,5 to 16.8/100 000 pop. between 2015 and 2017 (p &amp;lt; 0,01). The incidence rates among foreigners increased from 44.6 to 51.7/100 000 pop. (p &amp;lt; 0.01) and the proportion of tuberculosis cases among foreigners who arrived in France less than 2 years ago increased from 23% to 32% (p &amp;lt; 0.01), between 2015 and 2017. The incidence rates of tuberculosis cases increased particularly in men, foreigners, and recent migrants. Conclusions The incidence of tuberculosis increased in the Ile-de-France region in 2016 and 2017, particularly in newly arrived migrants. This situation requires actions to better detect and manage tuberculosis in this specific population. Key messages The incidence of tuberculosis increased in the Ile-de-France region. The incidence of tuberculosis increased in vulnerable population in relation with recent migration. </jats:sec