Impact of chronic irradiation of IMV 9096 and IMV 8614 strains of Pseudomonas aeruginosa on immunomodulatory properties of their lipopolysaccharide complex

The effect of chronic irradiation of Pseudomonas aeruginosa (P. aeruginosa) phytopathogenic strain IMV 9096 and saprophytic strain IMV 8614 at a dose rate of 0.19 µGy/s of γ-radiation in the dose field of 137Cs on the immunomodulatory properties of their lipopolysaccharide (LPS) has been investigated. It was shown that in the wild-type seedlings of Arabidopsis thaliana (A. thaliana) Col-0 pre-treatment with LPS 9096, isolated from both irradiated and non-irradiated bacterial culture, caused an increased harmful effect 2.8 - 5.6 fold when plants were then infected with bacteria of this strain. Seedling damage was more pronounced with the use of LPS, isolated from bacteria exposed to chronic radiation. In seedlings of mutant jin1 with impaired jasmonate signaling pre-treatment of LPS 9096 caused attenuation of the damage at 20 - 45 % when infected with P. aeruginosa 9096. Pre-treatment of Arabidopsis seeds with bacterial LPS 8614, obtained from both irradiated and non-irradiated P. aeruginosa 8614 cultures, had a non-significant effect (± 15 % over control). In mutant plants, jin1 pre-treatment of seeds with LPS 8614 led to increased damage when infected with P. aeruginosa IMV 9096 at 30 - 60 %. It was found that chronic irradiation of bacteria changes the immunomodulatory properties of their LPS and the effect depends on the bacterial strain. This effect is mediated by jasmonate and salicylate signaling systems.