Identificazione di fattori di virulenza nel fungo fitopatogenoFusarium culmorum

Fusarium culmorumis a major fungal pathogen of wheat, causing foot and root rot (FRR) and fusarium head blight (FHB). Symptons include pre- and post-emergence death of the seedlings. It causes significant yield and quality losses. This study shows the importance to select mutants ofF. culmorumaltered in their metabolic or morphological processes and impaired in level of virulence and aggressiveness during the first step of interaction between this fungus with the host plant. The function of many genes that are implicated in FRR on durum wheat seedilings is as yet unknown. Therefore, the characterization and identification of pathogenicity-related genes is essential in the build-up of alternative control methods against this disease. The mutants ofF. culmorumwere obtained by random and targeted insertional mutagenesis methods using the transposon mimp1. The transposon insertion into a gene region allows to tag the gene of interest. In vitro bioassays to identify altered phenotypic characters of revertants growing in different metabolic conditions (osmotic stress, oxidative stress) were carried out. In vitro and in planta assays of pathogenicity were also performed by placing durum wheat seeds on mycelium discs in a Petri dish or covered by steril soil. The results showed the presence ofF. culmorumrevertants with altered phenotypic characters, including stunted vegetative growth and loss of pathogenicity towards wheat stem base/root tissue.