L'utilisation de molécules stimulatrices de défense des plantes (SDP), également appelées inducteurs de résistance, constitute une alternative possible aux traitements fongicides conventionnels pour contrôler les maladies dues aux chanpignons phytopathogènes. Dans cette étude, nous avons mis en évidence que trois produits à caractère SDP (FSOV2, FSOV7 et FSOV10) protègent le blé (Triticum aestivum L.) contre la septoriose (Mycosphaerella graminicola, anamorphe Zymoseptoria tritici) lorsqu'ils sont utilisés de façon préventive, mais cette protection dépend fortement du cultivar considéré. Les cultivars Alixan, Premio et Altigo testés ici présentaient au départ des niveaux de résistance distincts à la septoriose. Les protections obtenues ne sont pas liées à un effet direct sur la germination des spores du champignon, mais à l'induction des mécanismes de défense chez le blé qui réduisent la nécrose foliaire et la sporulation du champignon. Ainsi, l'observation des différents stades du processus infectieux de M. graminicola en microscopie et le dosage des activités enzymatiques fongiques de dégradation des parois (CWDE) in planta révèlent que le niveau de protection induite varie avec le SDP appliqué et avec le cultivar traité. L'expression de neuf gènes impliqués dans différentes voies de défense, suivi par RTqPCR, et les activités enzymatiques peroxydase et phénylalanine ammonia lyase ont été mesurée au cours du temps, depuis le traitement par les SDP jusqu'à 5 jours après infection. Les résultats obtenus montrent, que les mécanismes de défense sont induits différemment en fonction du cultivar et en fonction du SDP appliqué. Ces résultats suggèrent que la réussite au champ des SDP est conditionnée de façon déterminante par le choix du couple SDP-cultivar. / The use of resistance inducers (RI) is a potential alternative to conventional fungicide treatments against plant fungal diseases. In the present study, we revealed that preventive applications of three RI conferred protection efficacies against M. graminicola, with protection levels varying with the wheat cultivar. Alixan, Premio and Altigo cultivars were previously known to exhibit distinct resistance levels to M. graminicola. The observed protections did not result from a direct effect on spore germination, but were related to the induction of wheat defense mechanisms. The induced resistances reduced foliar necrosis, as well as the sporulation level of the fungus. Microscopic observations of the infection process of M. graminicola and cell wall degrading enzymes (CWDE) activities measured in planta showed that the applied RI as well as the considered treated wheat cultivar influences the impact on the infection process and the protection efficacy. We investigated from the time of treatment until 5 days after inoculation plant peroxidase and phenylalanine ammonia lyase activities and the expression of nine genes involved in distinct defense pathways. Our results indicated that defense mechanisms are differently induced according both to the wheat cultivar and the RI. Therefore, the successful use of RI at the field level strongly depends on the RI-cultivar combination.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma. It is a molecular and prognostic heterogeneous disease. Three main genetic subtypes are called germinal center-like DLBCL (GC-like DLBCL), non-germinal center-like DLBCL (nonGC-like DLBCL) and primary mediastinal B-cell lymphoma (PMBL). These subtypes can be reliably distinguished only with usage of gene expression profiling (GEP). The GEP method can be applied only when fresh frozen tissue is available. The method is technically difficult and expensive. Thus, it is not used routinely. Since the DLBCL subtypes differ in prognosis, it is extremely important to be able to distinguish them. The presented thesis is focused on distinguishing of PMBL diagnosis in the group of DLBCL. Easily stored formalin-fixed, paraffin-embedded tissue (FFPE) and gene expression analysis using real-time quantitative polymerase chain reaction (RTqPCR) are used. In the first step, PMBL and DLBCL cases were distinguished with an internationally accepted clinical-pathological method. The agreement between clinical-pathological diagnosis and GEP is only 76%. In the presented text a genetic algorithm for PMBL/DLBCL distinguishing is suggested. It uses three carefully chosen genes and their expression is measured with RTqPCR. Both, the...

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma. It is a molecular and prognostic heterogeneous disease. Three main genetic subtypes are called germinal center-like DLBCL (GC-like DLBCL), non-germinal center-like DLBCL (nonGC-like DLBCL) and primary mediastinal B-cell lymphoma (PMBL). These subtypes can be reliably distinguished only with usage of gene expression profiling (GEP). The GEP method can be applied only when fresh frozen tissue is available. The method is technically difficult and expensive. Thus, it is not used routinely. Since the DLBCL subtypes differ in prognosis, it is extremely important to be able to distinguish them. The presented thesis is focused on distinguishing of PMBL diagnosis in the group of DLBCL. Easily stored formalin-fixed, paraffin-embedded tissue (FFPE) and gene expression analysis using real-time quantitative polymerase chain reaction (RTqPCR) are used. In the first step, PMBL and DLBCL cases were distinguished with an internationally accepted clinical-pathological method. The agreement between clinical-pathological diagnosis and GEP is only 76%. In the presented text a genetic algorithm for PMBL/DLBCL distinguishing is suggested. It uses three carefully chosen genes and their expression is measured with RTqPCR. Both, the...