Shifting the limits in wheat research and breeding using a fully annotated reference genome

Introduction: Wheat (Triticum aestivum L.) is the most widely cultivated crop on Earth, contributing about a fifth of the total calories consumed by humans. Consequently, wheat yields and production affect the global economy, and failed harvests can lead to social unrest. Breeders continuously strive to develop improved varieties by fine-tuning genetically complex yield and end-use quality parameters while maintaining stable yields and adapting the crop to regionally specific biotic and abiotic stresses. Rationale: Breeding efforts are limited by insufficient knowledge and understanding of wheat biology and the molecular basis of central agronomic traits. To meet the demands of human population growth, there is an urgent need for wheat research and breeding to accelerate genetic gain as well as to increase and protect wheat yield and quality traits. In other plant and animal species, access to a fully annotated and ordered genome sequence, including regulatory sequences and genome-diversity information, has promoted the development of systematic and more time-efficient approaches for the selection and understanding of important traits. Wheat has lagged behind, primarily owing to the challenges of assembling a genome that is more than five times as large as the human genome, polyploid, and complex, containing more than 85% repetitive DNA. To provide a foundation for improvement through molecular breeding, in 2005, the International Wheat Genome Sequencing Consortium set out to deliver a high-quality annotated reference genome sequence of bread wheat. Results: An annotated reference sequence representing the hexaploid bread wheat genome in the form of 21 chromosome-like sequence assemblies has now been delivered, giving access to 107,891 high-confidence genes, including their genomic context of regulatory sequences. This assembly enabled the discovery of tissue- and developmental stage–related gene coexpression networks using a transcriptome atlas representing all stages of wheat development. The dynamics of change in complex gene families involved in environmental adaptation and end-use quality were revealed at subgenome resolution and contextualized to known agronomic single-gene or quantitative trait loci. Aspects of the future value of the annotated assembly for molecular breeding and research were exemplarily illustrated by resolving the genetic basis of a quantitative trait locus conferring resistance to abiotic stress and insect damage as well as by serving as the basis for genome editing of the flowering-time trait. Conclusion: This annotated reference sequence of wheat is a resource that can now drive disruptive innovation in wheat improvement, as this community resource establishes the foundation for accelerating wheat research and application through improved understanding of wheat biology and genomics-assisted breeding. Importantly, the bioinformatics capacity developed for model-organism genomes will facilitate a better understanding of the wheat genome as a result of the high-quality chromosome-based genome assembly. By necessity, breeders work with the genome at the whole chromosome level, as each new cross involves the modification of genome-wide gene networks that control the expression of complex traits such as yield. With the annotated and ordered reference genome sequence in place, researchers and breeders can now easily access sequence-level information to precisely define the necessary changes in the genomes for breeding programs. This will be realized through the implementation of new DNA marker platforms and targeted breeding technologies, including genome editing

Stabilité et Structure d'Agrégats Catanioniques

Composition du juryDr. Isabelle RICO LATTES RapporteurPr. Jean François JOANNY RapporteurPr. Thomas ZEMB Directeur de thèsePr. Chantal LARPENT Président du juryPr. Olle SÖDERMAN ExaminateurPr. Bernd SMARSLY ExaminateurThe catanionic system hydroxide de cetyltrimetylammonium - myristic acid - water studied here has theadvantage to produce aggregates with controlled charge. So, the ternary phase diagram presents someinteresting aggregates (micelle, vesicle, disc, lamellar phase). The study of the CMC put in evidencesome strong interactions between monomers : the interaction parameter is equal to -10kT. On a microscopicpoint of view, the alkyl chains packing is hexagonal and we proved by WAXS and WANS thatthe head groups are liquid ordered. More over, the hydrogen bonds participate to the bilayer cohesion.The mechanical properties of the catanionic membrane are similar to the properties of phospholipids.We estimated the Young modulus to 100MPa by compressibility measurements (acoustic propagationand Langmuir trough). The thermodynamic properties studied by DSC showed that the chain meltingtransition depends on the sample composition.Le système catanionique CTAOH - C13COOH - H2O étudié forme des colloïdes de charge contrôléelorsque les tensioactifs sont mis en solution. Le diagramme de phase établi ici présente des agrégats particuliers(micelle, vésicule, disque, phase lamellaire). L'étude de la CMC a fait apparaître des interactionsfortes entre monomères : le coefficient d'interaction est de -10kT. Du point de vue microscopique, nousavons montré par diffusion couplée WAXS et WANS que les chaînes alkyl s'organisent suivant un réseauhexagonal et que les têtes ioniques conservent un ordre liquide. Par ailleurs, les liaisons hydrogèneparticipent à la cohésion du système, et les propriétés mécaniques de la membrane sont assez prochesde celles d'un phospholipide. Les mesures des compressibilités par propagation acoustique et cuve deLangmuir nous ont permis d'estimer le module d'Young à 100MPa. L'analyse calorimétrique par DSC amontré que la transition de fusion de chaînes dépend de la composition de l'échantillon

Microencapsulated Fragrances in Melamine Formaldehyde Resins: International Year of Chemistry

The process for making melamine formaldehyde microcapsules containing fragrant oil is well-known. Recently, this technology has been used to enhance the olfactory performance on fabrics. However keeping the fragrance in the capsule during storage, improving the olfactory benefit and releasing a low amount of formaldehyde is highly challenging. To answer these challenges, Givaudan has developed its own melamine formaldehyde microcapsule, called Mechacaps™, which is described in this article

High diversity of oilseed rape pollen clouds over an agro-ecosystem indicates long-distance dispersal

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Isolation and characterization of polymorphic microsatellites in the Potato Tuber Moth Tecia solanivora (Povolny, 1973) (Lepidoptera : Gelechiidae)

Nine polymorphic microsatellite markers were isolated from Tecia solanivora, one of the most serious pests of potato tubers in Central and South America. As found in other studies of Lepidoptera, development of microsatellites is a difficult task: in our case, despite the large number of clones sequenced (796), of which 70 were unique, only nine loci were found to be both variable, and in Hardy-Weinberg equilibrium, No null alleles were detected. The loci were tested in three other co-occurring Gelechiidae species, one of which was variable. These loci will be used to provide a greater understanding of the genetic changes occurring during the invasive process in this species

Exploitation of the 5BS physical map to complete the SKr crossability locus

International audienc

A cluster of putative resistance genes is associated with a dominant resistance to sunflower broomrape

International audienceKey messageThe HaOr5 resistance gene is located in a large genomic insertion containing putative resistance genes and provides resistance to O. cumana, preventing successful connection to the sunflower root vascular system.AbstractOrobanche cumana (sunflower broomrape) is a parasitic plant that is part of the Orobanchaceae family and specifically infests sunflower crops. This weed is an obligate parasitic plant that does not carry out photosynthetic activity or develop roots and is fully dependent on its host for its development. It produces thousands of dust-like seeds per plant. It possesses a high spreading ability and has been shown to quickly overcome resistance genes successively introduced by selection in cultivated sunflower varieties. The first part of its life cycle occurs underground. The connection to the sunflower vascular system is essential for parasitic plant survival and development. The HaOr5 gene provides resistance to sunflower broomrape race E by preventing the connection of O. cumana to the root vascular system. We mapped a single position of the HaOr5 gene by quantitative trait locus mapping using two segregating populations. The same location of the HaOr5 gene was identified by genome-wide association. Using a large population of thousands of F2 plants, we restricted the location of the HaOr5 gene to a genomic region of 193 kb. By sequencing the whole genome of the resistant line harboring the major resistance gene HaOr5, we identified a large insertion of a complex genomic region containing a cluster of putative resistance genes