Induction of defense compounds by seed treatment with plant growth-Promoting rhizobacteria Bacillus sp. against tomato fusarium wilt pathogen [electronic resource].

Includes reference.

Plant growth-promoting rhizobacteria (PGPR) Bacillus sp. strain TB281 was evaluated for plant growth promotion and biological control of tomato Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici. In the bacterized plants, there were significant growth increase in shoot length and fresh weight compared to untreated control. Seed bacterization using this Bacillus strain also decreased the number of diseased plants compared to non-bacterized controls. The present results also show that bacterized tomato plants contained higher levels of defense-related enzymatic activities in terms of peroxidase (PER), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) as well as endogenous phenolic compounds than non-bacterized ones. Maximum levels of defense enzymatic activities and endogenous phenolic compounds were found in Bacillus-treated plants growing in F. oxysporum-infested soil compared with their respective controls. The present data suggest that earlier and higher levels of enzymatic activities involved in phenylpropanoid metabolism and phenolic compounds were occurred in tomato plants treated with Bacillus TB281 in response to attack by F. oxysporum. The plant-pathogen interactions have also triggered the activities of defense enzymes and total soluble phenolics during the late primary events of the host-pathogen interaction, but during the secondary events the activities were declined sharply. Elevated levels of phenolics and defense related-enzymatic activities by Bacillus TB281 in tomato plants might have collectively contributed to induced resistance in tomato plants against tomato Fusarium wilt pathogen.

Summary in Arabic.

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