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

Yuliya Kolomiiets,Artur Likhanov,Ivan Grygoryuk,Yaroslav Blume,Lyudmila Butsenko

doi:10.2174/1874331501913010215

Abstract

Background: By inducing the production of inhibitory allelochemicals and mechanisms of systemic resistance plant growth promoting bacteria (PGPB) help plants to cope with stresses. Materials and Methods: 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. Results and Conclusion: 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.

Highlights

Bacterial canker of tomatoes is a significant problem for farmers and private households [1]
Five groups of plants were tested: 1 – plants without treatments, 2 – plants infected with C. michiganensis subsp. michiganensis ІZ-38, 3 – plants treated with a suspension of B. subtilis cells (109 CFU/cm3) and infected with C. michiganensis subsp. michiganensis ІZ-38, 4 – plants treated with a suspension of P. fluorescens cells (109 CFU/ml3) and infected with C. michiganensis subsp. michiganensis ІZ-38, 5 – plants treated with the suspension of A. chroococcum (109 CFU/cm 3) and infected with C. michiganensis subsp. michiganensis ІZ-38
At the period when the obvious signs of bacterial disease were observed, there was a profound transformation of the epithelial tissues of the leaves, of the palisade mesophyll

Summary

Introduction

Bacterial canker of tomatoes is a significant problem for farmers and private households [1]. Bacteria multiply in xylem vessels and form biofilm structures that accelerate colonization and movement of pathogens in plants [3]. The bacteria enter the fruits and predetermine their internal lesions. Plant infection with bacterial pathogens leads to the degradation of the constituent cell walls of blood vessels and xylem parenchyma, the development of chlorotic and necrotic sites and reduces the production of photosynthetic assimilates. Bacterial stress suppresses the physiological activity of tomato plants, which causes an imbalance in their nutrition. Excess nitrogen reduces the pH of cell juice as a source of nutrition for pathogens. Deficiency of К+ and Са2+ leads to a decrease in the turgor potential and the formation of thin cell walls, through which phytopathogens penetrate, and the lack of Zn2+, Mn2+, Cu2+ and Fe2+ disrupts the accumulation of protective products of plant secondary compounds, in parti-. By inducing the production of inhibitory allelochemicals and mechanisms of systemic resistance Plant Growth Promoting Bacteria (PGPB) help plants to cope with stresses

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Results

Conclusion