The relative expression of the seven genes involved in wheat defense reactions—namely, phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), lipoxygenase (LOX), allene oxide synthase (AOS), β-1,3-endoglucanase (PR-2), chitinase 2 (PR-3), and oxalate oxidase (OXO)—were analyzed using RT-qPCR in water- (control) and ulvan-treated plants prior to and after infection with Z. tritici. This evidence concerns the gene PRTN3 and infection.