No difference in accumulation of H2O2, as detected by 3, 3-diaminobenzidine (DAB) staining, was observed in leaves of pTRV2-Sl3-MMP- and pTRV2-GUS-infiltrated plants without infection of B. cinerea (Fig. 7a), indicating that silencing of Sl3-MMP itself did not affect the generation and accumulation of H2O2 in tomato plants. The gene discussed is MMP11; the disease is infection.