Genotoxic stress and DNA repair in plants: emerging functions and tools for improving crop productivity

Crop productivity is strictly related to genome
stability, an essential requisite for optimal plant growth/
development. Genotoxic agents (e.g., chemical agents,
radiations) can cause both chemical and structural damage
to DNA. In some cases, they severely affect the integrity of
plant genome by inducing base oxidation, which interferes
with the basal processes of replication and transcription,
eventually leading to cell death. The cell response to oxidative
stress includes several DNA repair pathways, which
are activated to remove the damaged bases and other
lesions. Information concerning DNA repair in plants is
still limited, although results from gene profiling and
mutant analysis suggest possible differences in repair
mechanisms between plants and other eukaryotes. The
present review focuses on the base- and nucleotide excision
repair (BER, NER) pathways, which operate according to
the most common DNA repair rule (excision of damaged
bases and replacement by the correct nucleotide), highlighting
the most recent findings in plants. An update on
DNA repair in organelles, chloroplasts and mitochondria is
also provided. Finally, it is generally acknowledged that
DNA repair plays a critical role during seed imbibition,
preserving seed vigor. Despite this, only a limited number of studies, described here, dedicated to seeds are currently
available.