【目的】研究转GO基因番茄的抗病机制。【方法】通过测定转GO基因番茄和对照未转基因番茄接种叶霉菌Fulvia fulva后，体内超氧物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)的活性变化。【结果】接种后转基因番茄株系的SOD、POD、CAT活性均比对照明显增加，且转基因番茄的活性高峰比对照早。转基因番茄在接种后PAL和PPO活性都出现2个活性高峰，且第2个峰值比第1个高，而对照只有1个活性高峰,其总体水平明显低于转基因番茄。用番茄叶霉病（Fulvia fulva）病原菌1.2.3.4生理小种侵染T1代转基因植株。【结论】 结果显示转基因番茄植株的抗病性有不同程度的提高，多数发病时间推迟，病情明显减轻。

【Objective】 The aim of the study is to determine the mechanism of resistance to Fulvia fulva of tomato transformed with GO gene.【Method】Superoxidase (SOD), peroxidase (POD), catalase (CAT), phenylalanine ammonialyase (PAL) and polyphenoloxidase (PPO) activities of three transgenic tomato lines and non-transgenic line (CK) were studied after inoculation. 【Result】The results showed that SOD, POD, CAT activities of transgenic tomato lines were much higher than that of non-transgenic tomato and showed a peak earlier than that of non-transgenic tomato line. Moreover the activities of PAL and PPO increased and showed two peaks in three transgenic tomato lines and only one peak in non-transgenic tomato line. 【Conclusion】T1 tomato plants infected with Fulvia fulva showed enhanced disease resistance, delayed disease symptoms and reduced leaf lesions at different levels.