Oxytranscriptome of soybean seedlings under short-term cadmium treatment

Despite the important role of reactive oxygen species (ROS) in plant stress response, little is known about their effects on RNA. Present study focuses on RNA oxidation in soybean seedlings exposed for a short time to cadmium (1-3 h, 10 mg/L Cd). Treatment with the metal had no effect on the level of common oxidative stress markers: superoxide anion accumulation, lipid peroxidation, protein carbonylation and reduced/oxidized glutathione ratio. On the other hand, 2 h-long exposure to Cd induced the formation of the most frequent oxidative modification of RNA, 8-hydroxyguanosine (8-OHG). The immunohistochemical detection of 8-OHG in the root cross sections demonstrated that this modification is accumulated in the inner cortex tissue, endodermis, protoxylem and phloem, and co-localizes with ROS. The sequencing of 8-OHG enriched poly(A)RNA revealed that transcripts differ in their susceptibility to the oxidation. The highly oxidized transcripts (HOTs) are associated with signalling, stress response and proteins folding. In turn, the lowly oxidized transcripts (LOTs) are involved in mitochondria functioning, response to stimuli and gibberellic acid (GA) metabolism.