Chronic ionizing radiation might suppress resistance to pathogens in aquatic plants without substantial oxidative...

Chronic ionizing radiation causes elevated levels of DNA damage and reactive oxygen species in plants. Aquatic ecosystems in Chornobyl zone, a major radiological disaster site, are contaminated by harmful radionuclides. We focused on explaining the biochemical mechanisms responsible for the susceptibility of a wild aquatic plant (common reed, Phragmites australis) grown in Chornobyl zone to biotic stress. The fungal infection assay indicated that life in a radionuclide-contaminated environment might compromise plant immunity. Proteome profiling identified 1,867 proteins and we selected several dozen proteins with consistently higher and lower abundance in the samples from the littoral of contaminated lakes by hierarchical clustering. Discordant expression of coding genes pointed to posttranscriptional regulation. Proteins that accumulated in reed upon chronic irradiation suggested a biochemically stable phenotype with effective protection against reactive carbonyls. Simultaneously, proteins that depleted in plants collected from the littoral of radiologically contaminated lakes indicated worse stress resilience and enhanced susceptibility to biotic agents. Furthermore, the quantification of antioxidant enzyme activities and carbonylated proteins rebutted the idea about substantial oxidative stress in chronically irradiated plants. We advocate the necessity to consider increased pathogen sensitivity while developing policies for the management of radionuclide-contaminated areas.