2.8.1. Transgenic Breeding for Fungal Resistance

In two independent studies, Jiang et al. generated transgenic broccoli plants overexpressing the cytosolic ascorbate peroxidase gene *BoAPX* and the WRKY transcription factor gene *BoWRKY6*; both of them obtained enhanced resistance to downy mildew [139,140]. *BoAPX*-overexpressing broccoli, with a lower level of electrical conductivity and a higher level of APX enzyme activity, exhibited significantly higher resistance to *Hyaloperonospora parasitica* infection, as well as to heat stress, than wild-type plants [139]. *BoWRKY6* overexpressing broccoli exhibited significantly increased resistance to downy mildew but varied from low to very high [140]; two of them, lines BWK14 and BWK31, exhibited very high resistance to downy mildew [140].
