Elucidating the Response of Diverse Faba Bean Genotypes to Powdery Mildew Infection

Faba bean (Vicia faba) is a temperate grain legume of major importance for food and feed. Powdery mildews are an important group of diseases in many crops, although in faba bean, it is still considered to be of only minor and local relevance. Here, we report the occurrence of powdery mildew in southern Spain, which was identified through ITS sequencing as Erysiphe trifolii. Resistance screenings allowed the identification of a wide range of responses to the disease, with accessions BPL-710 and ILB-4708 outstanding due to their high levels of resistance. Histological studies showed that the mechanisms of resistance may involve the inhibition of germination and impairment of fungal development, as shown by a limited number of primary and secondary hyphae compared to those of the susceptible accessions. This work permitted a better understanding of the interaction of faba bean and powdery mildew, laying the ground for breeding programs for resistance if needed in the future.