Structural Variation and Its Roles in Plant Genomes

Plant genomes exhibit extensive structural diversity generated by large-scale genomic alterations, collectively known as structural variations (SVs). Unlike single nucleotide polymorphisms (SNPs) and small insertions/deletions (indels), SVs can reshape genome architecture through changes in sequence content, gene dosage, regulatory landscapes, and chromosome organization. Recent advances in long-read sequencing (LRS), pan-genome construction, and multi-omics technologies have greatly expanded our ability to identify and interpret SVs across plant species. In this review, we summarize recent progress in understanding the formation mechanisms, classification, and functional consequences of plant SVs. We discuss major sources of SV generation, including transposable element activity, non-allelic homologous recombination (NAHR), horizontal gene transfer (HGT), and genome restructuring following polyploidization. We further highlight how LRS and graph-based pan-genomes overcome limitations of traditional linear reference genomes and enable more comprehensive characterization of genetic diversity. Beyond variant discovery, we emphasize the importance of integrating genomic, transcriptomic, epigenomic, proteomic, metabolomic, and spatial omics datasets to decipher how SVs influence gene regulation and complex agronomic traits. We also discuss current challenges, including repetitive genomes, polyploidy, computational complexity, and translation of SV knowledge into practical breeding applications. Together, these advances establish SV-centered genomics as a critical framework for understanding plant genome evolution and accelerating precision crop improvement.