Carotenoids’ influence on radiotolerance ofPantoea agglomerans, a plant pathogen

AIM: The aim of this study was to evaluate the effect of gamma radiation on the carotenoid content of two strains of the Enterobacteriaceae: Pantoea agglomerans. METHODS AND RESULTS: Pantoea agglomerans strains ATCC 49174 and RL1 were used for this study. Successive radiation treatments were performed to study the radiotolerance. Total carotenoids were obtained by multiple extraction using chloroform/methanol (2 : 1), quantified by measuring the optical density at 453 nm and their antioxidant activity measured by a colorimetric method. The D(10) studies were conducted using a UC-15A irradiator loaded with 60Co. Bacterial counts from various dilutions were carried out after irradiation. Strain ATCC 49174 irradiated at 1 kGy produced 4.3 times more carotenoids than the control, whereas carotenoid synthesis increased by 2.9-fold in the strain RL1. However, there was no significant difference in the D(10) values. CONCLUSION: Carotenoid increased production is influenced by gamma radiation but does not modify the tolerance to radiations. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first study to demonstrate the effects of gamma radiation on carotenoid production levels.