SYNERGISTIC ACTIVITY OF CHITINASES AND BETA-1,3-GLUCANASES ENHANCES FUNGAL RESISTANCE IN TRANSGENIC TOMATO PLANTS

Simultaneous expression of a tobacco class I chitinase and a class I b eta-1,3-glucanase gene in tomato resulted in increased fungal resistan ce, whereas transgenic tomato plants expressing either one of these ge nes were not protected against fungal infection. After infection with Fusarium oxysporum f.sp. lycopersici, a 36% to 58% reduction in diseas e severity was observed in resistant tomato lines. Two transgenic line s largely recovered from the initial infection by the time wild-type t omato plants had died. The overall results are consistent with the obs ervation that class I chitinases and class I beta-1,3-glucanases syner gistically inhibit the growth of fungi in vitro and provide the first experimental support to the hypothesis that such synergy can contribut e to enhanced fungal resistance in planta.