Induction of Bacterial Canker Resistance in Tomato Plants Using Plant Growth Promoting Rhizobacteria

By inducing the production of inhibitory allelochemicals and mechanisms of systemic resistance Plant Growth Promoting Bacteria (PGPB) help plants to cope with stresses.

In this study cell suspensions of Bacillus subtilis, Pseudomonas fluorescens or Azotobacter chroococcum were used to test the efficacy of these PGPB in inducing resistance in tomato (Lycopersicon esculentum Mill) against Clavibacter michiganensis subsp michiganensis, a bacteria known to cause canker disease. To test this hypothesis, seedlings of Chaika variety, characterized by short growing, early-ripening, high productivity and resistance against fusarium and the C. michiganensis strain ІZ-38 isolated in Kyiv were employed.

The use of cell suspensions of the PGPB B. subtilis, A. chroococcum or P. fluorescens induced an increment in the resistance of tomato plants against the causative agent of bacterial canker (C. michiganensis subsp. michiganensis) by 42–50%. PGPB in fact promoted in C. michiganensis infected tomato plants: i) the accumulation of chlorophyll a and b and carotenoids; ii) the thickening of the upper and lower epidermis of leaves; iii) the deposition of biopolymers with protective properties in epidermal cells; iv) the activity of the peroxidase enzyme and v) the net productivity of photosynthesis.