TheMedicago truncatulahypermycorrhizal B9 mutant displays an altered response to phosphate and is more susceptible toAphanomyces euteiches

Inorganic phosphate (Pi) plays a key role in the development of arbuscular mycorrhizal (AM) symbiosis, which is favoured when Pi is limiting in the environment. We have characterized the Medicago truncatula hypermycorrhizal B9 mutant for its response to limiting (P/10) and replete (P2) Pi. On P2, mycorrhization was significantly higher in B9 plants than in wild-type (WT). The B9 mutant displayed hallmarks of Pi-limited plants, including higher levels of anthocyanins and lower concentrations of Pi in shoots than WT plants. Transcriptome analyses of roots of WT and B9 plants cultivated on P2 or on P/10 confirmed the Pi-limited profile of the mutant on P2 and highlighted its altered response t…

Effet de la nutrition et du génotype sur les réponses de défense chez Medicago truncatula

Les organismes phytopathogènes sont responsables de la destruction d’environ 30% des récoltes. Malgré leur impact négatif sur l’environnement et la santé humaine, les produits phytosanitaires restent un des principaux moyens de lutte. Dans un cadre général de diminution de l’utilisation de ces produits, mon projet de thèse a pour objectif de mieux comprendre l’effet de la nutrition de la plante et de son génotype sur les mécanismes moléculaires impliqués dans ses réponses de défense vis-à-vis des pathogènes et ceci afin de définir des stratégies de lutte innovantes. Etude de l’effet des carences nutritionnelle sur la signalisation cellulaire et moléculaire des réponses de défense par analys…

Interaction between Medicago truncatula and the pathogenic oomycete Aphanomyces euteiches: effects of nitrogen nutrition and plant genotype

Plants are under the constant threat of microbial pathogens. To defend themselves, plants have developed immune responses (including for example synthesis of antimicrobial secondary metabolites, production of PR proteins or reinforcement of cell wall) that can lead to resistance. However, these plant defense responses are costly and lead plants to continuously face a dilemma regarding the partitioning of their available resources. In order to better understand relationships between plant nutrition and defense, we analyzed the impact of nitrogen (N) nutrition on the capacity of different M. truncatula genotypes to resist against A. euteiches, the causal agent of legume root rot disease. N st…

Effet de la nutrition azotée et du génotype de la plante sur la résistance de Medicago truncatula à Aphanomyces euteiches

Effects of plant nutrition and genotype on Medicago truncatula defense responses against Aphanomyces euteiches

SPEIPM; International audience

The Medicago truncatula hypermycorrhizal B9 mutant displays an altered response to phosphate and is more susceptible to Aphanomyces euteiches.

SPE IPM; National audience; Inorganic phosphate (Pi) plays a key role in the development of arbuscular mycorrhizal (AM) symbiosis, which is favoured when Pi is limiting in the environment. We have characterized the Medicago truncatula hypermycorrhizal B9 mutant for its response to limiting (P/10) and replete (P2) Pi. On P2, mycorrhization was significantly higher in B9 plants than in wild-type (WT). The B9 mutant displayed hallmarks of Pi-limited plants, including higher levels of anthocyanins and lower concentrations of Pi in shoots than WT plants. Transcriptome analyses of roots of WT and B9 plants cultivated on P2 or on P/10 confirmed the Pi-limited profile of the mutant on P2 and highli…

Effects of nitrogen nutrition and plant genotype on Medicago truncatula resistance against Aphanomyces euteiches

Effect of nitrogen nutrition on Medicago truncatula resistance against Aphanomyces euteiches

Nitrogen (N) is a major limiting factor for plant growth. N availability can also impact plant resistance to pathogens by regulating plant immunity. To better understand the links between N nutrition and plant defense, we analyzed the impact of N availability of plant on Medicago truncatula resistance to the root pathogen, Aphanomyces euteiches, taking into account plant genetic variability. This oomycete is considered as the most limiting factor for legume production. Two conditions of N nutrition, non-limiting or deprived in N, and ten plant genotypes were tested in vitro. The results showed that the resistance is modulated by nutritional conditions, depending on plant genotype. Analysis …

Effets de la nutrition et du génotype de la plante sur la résistance de Medicago truncatula à Aphanomyces euteiches

SPEIPMUBAGROSUPINRA; Dans la nature, les plantes ont la capacité de mettre en oeuvre des réponses immunitaires pour faire face aux microorganismes pathogènes. Cependant, ces réponses de défense sont coûteuses en énergie et conduisent la plante à détourner une partie de ces ressources destinées à d’autres traits de vie comme la croissance. Ce compromis défense/croissance est largement conditionné par la disponibilité extérieure en nutriments. Afin de mieux décrire et comprendre les liens entre la nutrition et la défense, nous avons analysé l’impact de la nutrition azotée et l’effet de la variabilité génétique végétale sur la capacité de la légumineuse Medicago truncatula à résister à un agen…