Oxidative RNA Modifications as an Early Response of Soybean (Glycine max L.) Exposed to Copper and Lead

Abstract

Plant exposure to metals is associated with the accumulation of reactive oxygen species, which mediate the oxidation of various molecules including lipids, proteins, and nucleic acids. The aim of the present study is the evaluation of the impact of short-term Cu and Pb treatment on oxidative events in the roots of soybean seedlings, with special emphasis on RNA oxidation. The results show that an increase in total RNA oxidative modification, 8-hydroxyguanosine (8-OHG), constitutes a very early response to both applied metals, observed already within the first hour of treatment. Exposure to Cu and Pb resulted also in the increase in superoxide anion and hydrogen peroxide levels and intensified lipid peroxidation. However, these responses were most prominent after longer treatment times. On the other hand, no changes were observed in the level of protein carbonylation. It can be concluded that 8-OHG enrichment in total RNA constitutes one of the earliest reactions to metals, which precedes the symptoms of oxidative stress.

Mitochondria Specific Antioxidant, MitoTEMPO, Modulates Cd Uptake and Oxidative Response of Soybean Seedlings

“…An elevated 8-hydroxyguanosine (8-OHG) level in the RNA is a recently described marker of short-term metal stress in plants [ 23 , 24 ]. The results of the present study showed that treatment with Cd resulted in a significant increase in the level of 8-OHG in total RNA isolated from seedling roots ( Figure 4 ).…”

“…The information on transcripts oxidation in plants is still very limited, with less than 10 articles published overall (Scopus database search with terms “RNA oxidation” and “plant*”, date of access 19 October 2022). However, rapid induction of 8-OHG formation in RNA has been observed in plants response to metals [ 23 , 24 ]. In the cited studies, 8-OHG accumulation occurred in earlier periods (within the first 3 h of treatment) and reached the control levels after 24 h. Thus, the obtained results showing 8-OHG induction also after 48 h of treatment indicate fluctuations in Cd-dependent 8-OHG accumulation, possibly corresponding to distinct waves of ROS production [ 8 ].…”

The role of epigenetic and epitranscriptomic modifications in plants exposed to non-essential metals

“…Recently, the first epitranscriptomic reports revealed that exposure to Cd modulated the pattern of transcript m6A methylation in barley and soybean plants ( Su et al., 2022 ; Han et al., 2023 ). Treatment with Cd and Pb also lead to early increases in the level of oxidation dependent RNA modification –8-hydroxyguanosine (8-OHG), although the role of 8-OHG in metal response is still to be elucidated ( Chmielowska-Bąk et al., 2018 ; Chmielowska-Bąk et al., 2022 ).There are premises indicating that epigenetic and epitranscriptomic changes contribute to the enhancement of plant metal tolerance e.g. through protection of DNA from damage, modulation of the expression of genes related to metal transport, cellular signalling and stress defense leading to hampered metal uptake and more efficient inter-cellular distribution as well as to accumulation of protective compounds (e.g.…”

“…In soybean seedlings, short term treatment with Cd and Pb induced 8-OHG accumulation in total RNA and/or poly(A) RNA. The observed response was rapid, observed only after few hours of metal exposure, and preceded the symptoms of oxidative stress ( Chmielowska-Bąk et al., 2018 ; Chmielowska-Bąk et al., 2022 ). However, the exact role of this early 8-OHG formation in plants is still to be revealed.…”