Pn-AMPs, the hevein-like proteins from Pharbitis nil confers disease resistance against phytopathogenic fungi in tomato, Lycopersicum esculentum

The antifungal activity of hevein-like proteins has been associated with their chitin-binding activities. Pn-AMP1 and Pn-AMP2, two hevein homologues from Pharbitis nil, show in vitro antifungal activities against both chitin and non-chitin containing fungi. Purified Pn-AMPs retained antifungal activities only under non-reducing conditions. When Pn-AMP2 cDNA was constitutively expressed in tomato (Lycopersicon esculentum) plants under the control of CaMV35S promoter, the transgenic plants showed enhanced resistance against both the non-chitinous fungus Phytophthora capsici, and the chitin-containing fungus Fusarium oxysporum. Thus, the chitin component in the fungal cell wall is not an absolute requirement for Pn-AMP's antifungal activities. These results when considered together suggest that Pn-AMPs have the potential for developing transgenic plants resistant to a wide range of phytopathogenic fungi.