Plant DNA Damage Response and Repair Pathways: from Molecular Mechanisms to Crop Improvement

Abstract

Genome stability is essential for plant growth, development, reproduction and adaptation under changing environmental conditions. Plants are continuously exposed to endogenous metabolic by-products and environmental stresses that generate diverse DNA lesions and threaten genome integrity. This review synthesises the molecular basis of plant DNA damage responses and major repair pathways, with emphasis on their coordination and relevance to crop improvement. The plant DNA damage response integrates lesion sensing, signal transduction, cell-cycle regulation, chromatin remodelling and repair. ATM and ATR kinases, together with the plant-specific transcription factor SOG1, coordinate responses to double-strand breaks, replication stress and other forms of DNA damage. Major repair mechanisms include direct reversal repair, base excision repair, nucleotide excision repair, mismatch repair, homologous recombination, classical non-homologous end joining and alternative end joining. Their combined activities support genome stability, stress adaptation, photosynthetic performance and reproductive fitness. DNA repair pathway choice also influences the outcomes of mutagenesis and CRISPR/Cas-mediated genome editing, including gene knockout, targeted insertion and allele replacement. Integration of DNA repair biology with molecular breeding, genomic selection, speed breeding and multi-omics approaches provides a framework for improving editing precision and exploiting useful genetic variation. A more integrated understanding of plant DNA repair regulation may therefore support the development of crop varieties with improved resilience to adverse environmental conditions.