Pseudomonas putida - Induced response in phenolic profile of tomato seedlings (Solanum lycopersicum L.) infected by Clavibacter michiganensis subsp michiganensis

Efficacy of Pseudomonas putida (CKPp9) was tested under in vitro and in vivo conditions for their ability to plant growth promoting characteristics in tomato seedlings against Clavibacter michiganensis subsp. michiganensis (CmmGo2) infection. A significant difference was observed between bacterized tomato seedlings with P. putida (CKPp9) and the other treatments (P < 0.01). Also, CmmGo2 was detected significant difference the least plant growth parameters for tomato seedlings (P < 0.01). To correlate the induction of phenolic compounds by the CKPp9 with disease resistance, qualitative and quantitative modifications of phenolic compounds in tomato seedlings were observed in different treatments. High performance liquid chromatographic (HPLC) analysis of the leaves of the CKPp9-treated, CmmGo2-treated, and non-treated (control) plants showed the presence of chlorogenic acid, caffeic acid, catechin and rutin with varied amounts in the CKPp9 treated as well as CmmGo2-treated and non-treated (control) plants. Maximum accumulation of catechin was observed in plants treated with the CKPp9 strain + CmmGo2 strain which was almost 10 times higher than the CKPp9-treated plants and also significantly high when compared to other treatments. A direct relationship between the level of catechin and seedling survivability was observed. P. putida-mediated induction of phenolic compounds as a biochemical barrier in tomato seedlings against C. michiganensis subsp. michiganensis infection is envisaged. (C) 2016 Elsevier Inc. All rights reserved.