DNA Damage and Repair Mechanism in Duckweed (Spirodela polyrhiza) Under Ultraviolet (UV-B) Radiation Stress

Overview

In living organisms, DNA is a critical macromolecule; its stability and integrity are vital for the normal functioning of cellular processes, such as DNA replication repair. Sunlight is a significant source of ultraviolet (UV) radiation. Excessive exposure to UV-Bradiation can cause damage to DNA structure by introducing DNA lesions such as cyclobutane-pyrimidine dimers (CPDs) and 6- 4 photoproducts (6 -4PPs). These negatively affect the physiological processes of living organisms. In this study, duckweed (Spirodela polyrhiza) plantlets were exposed to different UV-Bexposure times. After UV -Bexposure, plantlets were recovered under normal growth conditions and sampled at 0 hours, 12 hours, and 24 hours for genomic DNA damage analysis. The quality and integrity of the genomic DNA were tested by gel electrophoresis. Genomic DNA was probed on a slot-blot experiment for antibodies against the CPDs/6 -4PPs to detect damaged DNA and DNA repair capacity. Our results suggest that duckweed plantlets at 0 hours of post -UV-Brecovery had the strongest CPDs/6-4PPs signal intensity; thus, in these samples, the DNA repair mechanism did not have enough time to repair the damaged DNA. Weaker CPDs/6-4PPs signals were observed in the 12 and 24-hour recovery times post -UV-Btreatment. In situ visualization by DAB staining revealed increased H 2O2 in the 0 -hour post -UV-Brecovery plantlets. DNA damage, DNA repair mechanism, and accumulation of H 2O2 in duckweed are UV -B d ose-dependent. Our work suggests that duckweed is ideal for studying UV -B-mediated DNA damage as an alternative to mammalian systems to understand the effect of climate change on plant and human health.

Competition history

• JSHS 2025 Category not listed

Resources

• National JSHS abstract book ↗

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