The effects of induced resistance to bacterial wilt by avirulent strains on the defense enzymes and inhibitory activities of crude extracts in tomato leaves

Avirulent strains of Ralstonia solanacearum (Atm044 and Asp061) obtained by UV mutagenesis were studied on resistance induction on tomato plants. After the inoculation of the avirulent strains, a significant increasing of the activities of peroxidase (POD),phenylanine ammonia lyase (PAL),polyphenoloxidase (PPO) and superoxide dismutase (SOD) in tomato plants was observed. The crude extracts from avirulent strain treated plants showed a strong inhibitory effect on virulent strains in vivo as well as in vitro . Our results indicated that the avirulent R.solanacearum strains induced tomato resistance possibly through triggering the plant defense reactions.