Etude pilote sur le petit déjeûner comme marqueur de l'état nutritionnel des personnes âgées

PARIS-BIUM (751062103) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

μLAS technology for DNA isolation coupled to Cas9-assisted targeting for sequencing and assembly of a 30 kb region in plant genome

International audienceCas9-assisted targeting of DNA fragments in complex genomes is viewed as an essential strategy to obtain high-quality and continuous sequence data. However, the purity of target loci selected by pulsed-field gel electrophoresis (PFGE) has so far been insufficient to assemble the sequence in one contig. Here, we describe the μLAS technology to capture and purify high molecular weight DNA. First, the technology is optimized to perform high sensitivity DNA profiling with a limit of detection of 20 fg/μl for 50 kb fragments and an analytical time of 50 min. Then, μLAS is operated to isolate a 31.5 kb locus cleaved by Cas9 in the genome of the plant Medicago truncatula. Target purification is validated on a Bacterial Artificial Chromosome plasmid, and subsequently carried out in whole genome with μLAS, PFGE or by combining these techniques. PacBio sequencing shows an enrichment factor of the target sequence of 84 with PFGE alone versus 892 by association of PFGE with μLAS. These performances allow us to sequence and assemble one contig of 29 441 bp with 99% sequence identity to the reference sequence

The complete genome sequence of Orobanche cumana (sunflower broomrape)

Trabajo presentado en el 14th World Congress on Parasitic Plants (From genome to field), celebrado en Asilomar (California) el 24 y 25 de junio de 2017.Orobanche cumana (sunflower broomrape) is an obligate parasitic plant that specifically infects sunflower (Helianthus annuus). It is one of the main limiting factors of sunflower crop in Eastern Europe, Spain and Asia. In 2007, the first infested fields have been reported in France. Breeding for resistance in sunflower was successful but new more virulent races of O. cumana often overcame the resistance genes. The first developmental stages of O. cumana occur underground. The germination of the seeds is first stimulated by sunflower root exudates before entering the host root through a haustorium. Without roots nor chlorophyll, O. cumana depends on sunflower for water and nutrients supply. It connects to the vascular system of the sunflower root and store metabolites in a tubercle before emerging a flowering shoot. The inactivation of these developmental stages is a key resistance mechanism in sunflower. A better understanding of the biology of O. cumana will help to identify new resistance processes and resistance genes in sunflower. In the frame of a collaborative project between French and Spanish research institutes, we have produced a first version of the 1.42 Gb genome sequence of O. cumana by combining PacBio sequencing, optical mapping and genetic map. More than twenty transcriptomic RNA-seq experiments from O. cumana were used for annotating the genome sequence. This first sequence assembly (622 scaffolds, 1.38Gb, N50=5.9Mb) and its annotation will be provided through a Web Genome Browser to the public research community. Our strategy to obtain and finalize the genome assembly as well as results on population diversity will be presented. The genome sequence of O. cumana will enable the characterization of its physiology and development. Avirulence genes should be identified more efficiently and, as putative interactor with sunflower proteins, should help in identifying new resistance genes in sunflower. This resource will help in understanding parasitic plants’ biology and evolution, like parasitism capacity acquisition.N

Whole-genome landscape of Medicago truncatula symbiotic genes

This Whole Genome Shotgun project has been deposited at DDBJ/ENA/GenBank under the accession PSQE00000000.International audienc

Population genomics of apricots unravels domestication history and adaptive events

Among crop fruit trees, the apricot (Prunus armeniaca) provides an excellent model to study divergence and adaptation processes. Here, we obtain nearly 600 Armeniaca apricot genomes and four high-quality assemblies anchored on genetic maps. Chinese and European apricots form two differentiated gene pools with high genetic diversity, resulting from independent domestication events from distinct wild Central Asian populations, and with subsequent gene flow. A relatively low proportion of the genome is affected by selection. Different genomic regions show footprints of selection in European and Chinese cultivated apricots, despite convergent phenotypic traits, with predicted functions in both groups involved in the perennial life cycle, fruit quality and disease resistance. Selection footprints appear more abundant in European apricots, with a hotspot on chromosome 4, while admixture is more pervasive in Chinese cultivated apricots. Our study provides clues to the biology of selected traits and targets for fruit tree research and breeding.Organisation et montée en puissance d'une Infrastructure Nationale de Génomiqu