Significant efforts have been directed toward improving grapevine resistance to bacterial crown gall disease (Agrobacteriumvitis) and Pierce’s disease (PD) (Xylella fastidiosa). A number of non-plant antimicrobial peptides from various sources were tested for their in vitro efficacy against A. vitis and X. fastidiosa prior to func-tional analyses [82,83]. Genetically modified grapevines expressing the animal-derived lyticpeptide, magain in, and truncated Agrobacterium virE2 protein, exhibited decreased crown gall symptoms caused by A. vitis [81,84]. Other lytic peptides such as cecropin,mellitin and their hybrid derivatives, LIMA1 and LIMA 2, were inserted into elite table and wine grape cultivars