UV-C-induced reactive carbonyl species are better detoxified in the halophytic plants Salicornia brachiata and Arthrocnemum macrostachyum than in the halophytic Sarcocornia fruticosa plants

Abiotic stress-induced reactive carbonyl species (RCS) accumulation in plants stimulates oxidative stress by DNA adduct formation, protein carbonylation, and antioxidant pool depletion, triggering senescence or programmed cell death. RCS accumulation under abiotic stress has rarely been studied in halophytic plants that are adapted to highly saline environments. In the current study, exposure to UV-C irradiation resulted in a higher RCS accumulation in the halophytic Sarcocornia fruticosa ecotypes VM and EL than in Salicornia brachiata (SB) and Arthrocnemum macrostachyum (AM). Accordingly, SB and AM recovered better, whereas VM and EL showed significant damage 14 days after UV-C application. Reduced aldehyde oxidase (AO) activity, recently shown to detoxify carbonyl aldehydes in Arabidopsis plants, is likely responsible for the significantly higher RCS accumulation and damage in the VM and EL plants. As evidence for this, the VM plants exposed to exogenously applied 3 mM of malondialdehyde or 3 mM of benzaldehyde exhibited decreased AO activity, which resulted in the accumulation of endogenous RCS and severe damage, including mortality. In contrast, the AM plants were able to detoxify RCS by AO activity enhancement, exhibiting recovery after 25 days. These results highlight the role of RCS accumulation in VM and EL plant tissue damage, while improved AO activity, which resulted in improved RCS detoxification in SB and AM, promoted better recovery.