Plant regeneration refers to the remarkable capacity of differentiated or wounded somatic cells to regain pluripotency or totipotency, enabling the formation of new organs or even whole plants. This developmental plasticity proceeds primarily through two major pathways-de novo organogenesis and somatic embryogenesis-each controlled by coordinated activities of key transcription factors (e.g., WUSCHEL, PLETHORA, BABY BOOM), auxin-cytokinin hormonal networks, and epigenetic regulators that govern dedifferentiation, proliferation, and redifferentiation. These processes underpin modern tissue culture systems used for clonal propagation, transformation, and trait engineering. Recent progress has substantially clarified the gene regulatory circuits, hormone crosstalk, and chromatin remodeling events that drive regenerative competence. Importantly, emerging evidence now highlights that successful regeneration cannot be achieved by manipulating single genes or hormones in isolation. Instead, overcoming current limitations-particularly genotype-dependent recalcitrance-requires a systems-level, integrative strategy that simultaneously modulates morphogenic regulators, dynamically reshapes hormone distribution, and transiently relaxes epigenetic constraints. This conceptual shift toward coordinated regeneration system engineering offers a promising framework for achieving predictable, efficient, and broadly transferable regeneration protocols across crops, woody perennials, and recalcitrant species, thereby strengthening the biotechnological foundation for sustainable and resilient plant production.

In conifers, compression wood (CW) with a high lignin content forms at the base of the stem or branch in response to gravity, which is a good model system for studying lignin-rich wood formation. In this study, we identified and characterized the laccase gene family (PdeLAC) in Korean red pine (Pinus densiflora), which is integral to monolignol polymerization. Phylogenetic analysis of 54 PdeLAC genes with those from gymnosperms (i.e., Pinus taeda and Picea abies) and angiosperms (i.e., Populus trichocarpa, Arabidopsis thaliana, and Oryza sativa) revealed their categorization into five groups, highlighting distinct evolutionary relationships compared to angiosperms. Gene structure and motif analysis showed conserved copper-binding loops and variable substrate-binding loops, suggesting functional diversity. Expression profiling indicated that 23 PdeLAC genes, including three (PdeLAC28, PdeLAC1, and PdeLAC31) homologous to AtLAC17, were upregulated in developing xylem during the growing season, particularly in CW. Transgenic poplars overexpressing PdeLAC28 exhibited increased xylem area, cell wall thickness, and Klason lignin content, underscoring its role in lignin biosynthesis and CW formation. This study provides valuable insights into the molecular regulation of lignin biosynthesis in CW of P. densiflora, setting a foundation for advancing our understanding of wood formation mechanisms in gymnosperms.

The genus Pinus (~115 species) represents a cornerstone of boreal and temperate forests and plays a central role in global forestry, industrial applications, and carbon sequestration. Their distinctive biology—including exceptionally large genomes, guaiacyl-rich lignin, tracheid-based xylem, and pronounced seasonal growth regulation—makes pines both scientifically compelling and technically challenging to study. Recent advances in genomics and transcriptomics, supported by emerging multi-omics and computational frameworks, have significantly advanced our understanding of the molecular architecture of wood formation, including key processes such as NAC–MYB regulatory cascades, lignin biosynthesis pathways, and adaptive processes such as compression wood development. Yet functional studies remain limited by low transformation efficiency, regeneration difficulties, and a scarcity of conifer-optimized genetic tools. This review highlights recent breakthroughs in single-cell and spatial transcriptomics, CRISPR-based genome editing, synthetic promoter design, and machine learning-driven regulatory network prediction and comprehensively examines translational applications in biomass improvement, lignin engineering, stress resilience, and industrial biotechnology. By expanding the research frontiers of Pinus, we aim to connect molecular discovery with applied forestry and climate mitigation strategies.