Influence of PGPR and AMF on antioxidant activity, lycopene and potassium contents in tomato

In this study, the impact of inoculating tomato (Lycopersicon esculentum F1 Hybrid, GS -15) roots with plant growth-promoting rhizobacteria (PGPR) and Arbuscular Mycorrhiza Fungi (AMF) on fruit quality was evaluated. The control treatment was non-inoculated, the PGPR treatments were inoculated with Pseudomonas putida, Azotobacter chroococcum and Azosprillum lipoferum, and the AMF treatment was inoculated with mixture of Glomus intaradics + Glomus mossea + Glomus etunicatum. Compared to the control treatment, phytochemical factors, containing lycopene and antioxidant activity, shoot and fruit potassium increased by PGPR and AMF treatments. Maximum lycopene and antioxidant activity were found in plants of the Pseudomonas + Azotobacter + Azosprillum + AMF treatment. A positive correlation between lycopene with shoot potassium (r = 0.89, p<0.01) and fruit potassium (r = 0.86, p<0.01) was found. Minimum antioxidant activity was observed in plants of the Pseudomonas + Azotobacter treatment, but when AMF were added to this treatment, antioxidant activity increased significantly. In all treatments, shoot and fruit potassium increased when PGPR and AMF were used together. It was found that the application of Pseudomonas + Azotobacter + Azosprillum + AMF treatment had the most effect on lycopene, antioxidant activity and potassium contents on tomato.