CONICET | Buscador de Institutos y Recursos Humanos

Fusarium poae has been considered as a minor species among those that cause the FHB disease but in recent years several researchers have documented a high frequency of occurrence in several crops such as wheat and barley. Evaluating the interaction between Fusarium poae with the model plant Arabidopsis thaliana will contribute to the knowledge about plant defense against this pathogen. We evaluated the ability of F. poae to produce symptoms in Arabidopsis thaliana leaves by using two different methods. Moreover, we analyzed the defense of A. thaliana against F. poae using SA, JA and ET mutants and we monitored the expression level of genes involved in the main signaling pathways related to plant defense. Symptoms were observed in the inoculated leaves which allow demonstrating, as a first step, the ability of F. poae to infect A. thaliana leaves. Moreover, the results demonstrated that the npr1-1 mutants presented low symptoms compared to Col-0, etr2-1 and coi1-1 and that the coi1-1 mutant was the most susceptible genotypes followed by etr2-1 genotypes. The RT-PCR of several genes involved in plant defense revealed that PDF1.2, CHI/PR3 and ERF1, three important JA-ET responsive genes and NPR1 and PR1, which are regulated by SA signaling, were expressed upon F. poae inoculation. Our results suggest that JA and ET could play a key role in Arabidopsis leaves defense against F. poae. Therefore, although SA responsive genes were expressed in the inoculated leaves compared to control, the low symptoms observed in npr1-1 mutants indicate that functional SA would not be required for plant defense to F. poae. In conclusion, our results represent the first evaluation of the response of the main A. thaliana phytohormones involved in plant defense in the presence of F. poae.