ETUDE DE LA STRUCTURE ET DE L'EXPRESSION DES GENES CODANT POUR DES ENZYMES OXYDATIVES DU BLE DUR (TRITICUM DURUM DESF)

MONTPELLIER-SupAgro La Gaillarde (341722306) / SudocSudocFranceF

Détection de transgènes dans les aliments issus de plantes transgéniques

National audienc

Etude de l'expression des gènes de blé (triticum durum et triticum aestivum) au cours du développement du grain et en conditions de stress abiotiques (approche par RT-PCR quantitative en temps réel)

Les stress abiotiques posent de réels problèmes pour la culture du blé et menacent de ce fait l'approvisionnement en denrées alimentaires de base dans de nombreuses régions du globe. Nous avons porté notre intérêt sur des gènes codant pour des protéines LEA des groupes 2 et 4, des protéines LEA-cognate, des métallothionéines, des protéines à doigt de zinc et des peroxyrédoxines. Nous avons employé la RT-PCR quantitative en temps réel pour établir les profils d'accumulation des transcrits de ces gènes dans le grain de blé en cours de développement ainsi que dans des plantules de blés soumises à divers stress abiotiques et à l'application d'acide abscissique. Les résultats obtenus, nous ont permis de mettre en évidence l'implication de ces gènes dans la réponse du blé aux stress abiotiques et de formuler des hypothèses quant aux fonctions des protéines qu'ils codent ainsi que des perspectives que nous pouvons en attendre pour l'amélioration de la tolérance des blés à ces stress.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

Organismes génétiquement modifiés, détection et étiquetage des produits qui en sont issus

National audienc

La PCR quantitative en temps réel : application à la quantification des OGM

Suite à l’obligation d’étiquetage, au seuil de 1 %, des aliments contenant des OGM autorisés, il est nécessaire de disposer de méthodes fiables de quantification. Pour répondre à cette obligation, la technique de PCR quantitative en temps réel semble actuellement la mieux adaptée. Son principe, ses avantages et sa mise en oeuvre pour la détermination de la teneur en OGM de farines de soja sont présentés. Les PCR simplex et duplex sont comparées

La PCR quantitative en temps réel : application à la quantification des OGM

24 ref.National audienc

Puroindoline-a and puroindoline-b interact with the Saccharomyces cerevisiae plasma membrane through different amino acids present in their tryptophan-rich domain

UMR DAP équipe DGBInternational audiencePuroindolines are two small, basic cysteine-rich proteins isolated from Triticum aestivum seeds and characterized by a tryptophan-rich domain. They form the molecular basis of wheat grain hardness and display antimicrobial activity that may contribute to plant defence. Their antimicrobial activity is presumed to be due to their hydrophobic tryptophan-rich domain. However, little is known about their mode of action and there is no in vivo evidence that the binding of puroindolines to membranes is mediated by their tryptophan-rich domain. In this study, using a yeast complementation assay, we showed that puroindolines interact with the Saccharomyces cerevisiae plasma membrane. By site-directed mutagenesis of their tryptophan-rich domain, we determined that two tryptophan residues (W41 and W44) are mandatory for interaction of puroindoline-a with the yeast membrane whereas interaction of puroindoline-b depends on lysine residues. These results highlight that other residues than tryptophan play a critical role in the interaction of puroindolines with membranes, and probably their affinity for lipids and antimicrobial activitie

Quantification of common wheat adulteration of durum wheat pasta using real-time quantitative polymerase chain reaction (PCR)

International audienc

Detection and discrimination of cereal and leguminous species in chestnut flour by duplex PCR

Equipe DGB, ex-UMR PIAInternational audienceChestnut and chestnut-derived products are quite expensive and thus a possible target for fraudulent labeling. To obtain a French Label of Origin, chestnut producers need to certify the purity of their products. Chestnut-derived products are consumed by people who may suffer from celiac disease or are allergic to cereals. For these reasons, we developed a qualitative PCR-based method to detect cereal and leguminous species in chestnut flour. The presence of common wheat and barley was determined by amplifying part of the puroindoline-a gene, the presence of rye by amplifying part of the secaloindoline-a gene, the presence of durum wheat, rice, maize and chickpea by amplifying part of lipid transfer protein genes, the presence of oat by amplifying part of a thionin gene, the presence of kidney bean by amplifying part of a late embryogenesis- abundant protein, the presence of soybean by amplifying part of a lectin gene and the presence of fava bean by amplifying part of a nodulin gene. A chestnut thaumatine gene was used as control. PCR conditions were optimized to detect 1% of adulteration. Duplex PCR and specially designed sets of primers that allow amplification of several related species limited the number and cost of analyses required. Interpretation of the results is facilitated by using a decision tre

Comparative expression of five Lea genes during wheat seed development and in response to abiotic stresses by real-time quantitative RT-PCR

61 ref.International audienceGene expression profiles of group 2 (dehydrins) and group 4 Late embryogenesis abundant (Lea) genes in developing seeds of Triticum durum and T. aestivum and in coleoptiles and coleorhizae of T. durum seedlings were monitored by real-time quantitative RT-PCR. The five genes exhibited clear differences in their accumulation pattern in wheat seed and in response to dehydration, low temperature, salinity and ABA. Td29b, Td16 and Td27e gene transcripts accumulate late in embryogenesis as expected for Lea genes, Td11 gene transcripts were present throughout seed development whereas no Td25a gene transcripts were detected in seeds. Drastic changes in the relative levels of Td29b, Td16, Td27e and Td11 transcripts occurred at the shift between the cell expansion and desiccation phases. All genes except the Td11 gene are more highly induced by dehydration in coleorhizae than in coleoptiles. In contrast, response to low temperature, salinity or ABA is higher in coleoptiles than in coleorhizae. Depending on both the gene and on the type of stress, a wide range of induction levels (8- to 100,000-fold) was observed