The WUSCHEL-related homeobox (WOX) transcription factors (TF) regulate critical developmental processes in plants, including organ formation and stem cell maintenance. Although characterized in model species, the WOX family remains unexplored in passion fruit (Passiflora edulis). In this study, 10 WOX genes were identified in passion fruit, which are distributed across six chromosomes. We analyzed the phylogenetic relationships, gene structure, conserved motifs, and syntenic relationships of the PeWOX genes. Multiple sequence alignment analysis revealed strong conservation of the homeodomain region among WOX TF family members. Phylogenetic reconstruction further demonstrated that the 10 identified PeWOX genes in passion fruit could be classified into three distinct evolutionary clades: the WUS clade, the Intermediate clade, and the Ancient clade. The conserved motif and gene structure of WOX TF family members in the same evolutionary clade were highly consistent. Expression analysis based on RNA-seq and RT-qPCR showed that most PeWOX genes were expressed during ovule development. The expression level of PeWOX genes varies with different stress conditions. Subcellular localization analysis of tobacco leaf epidermal cells showed that PeWOX3/7/10 proteins were localized in the nucleus and cell membrane. Collectively, this study lays a foundation for future functional studies of passion fruit WOX genes.

Growth-Regulating Factors (GRFs) are plant-specific transcription factors that, together with GRF-Interacting Factors (GIFs) and under post-transcriptional control by miR396, coordinate cell proliferation and expansion to define organ size. This GRF–GIF–miR396 regulatory module holds major agronomic importance, shaping leaf architecture, source–sink relationships, nitrogen-use efficiency (NUE), and stress resilience in crops. Upregulation of specific GRF genes has been shown to enhance leaf width, yield potential, and other important agronomic traits. Synthetic GRF–GIF chimeras have revolutionized regeneration and genome editing in multiple crop species, revealing both successes and species-specific limitations. Expanding GRF/GIF gene families and functional analyses across various crops highlight conserved developmental functions with variable outcomes, including improved drought and salinity tolerance through sustained canopy growth. This review, focused on crop systems, integrates current advances in GRF-regulated leaf development, their contributions to abiotic and biotic stress adaptation, and the emerging utility of GRF–GIF chimeras. Finally, it outlines key challenges and future opportunities for leveraging GRFs in designing climate-resilient, high-efficiency crop ideotypes.

The genus Passiflora includes species important for fruit production, ornamental value, and breeding programs. Conventional methods, such as seed propagation and vegetative cuttings, face challenges like genetic heterogeneity, pathogen transmission, and long juvenile phases, limiting large-scale cultivation and breeding efficiency. In vitro culture technologies are essential for clonal propagation, germplasm conservation, and improving Passiflora species using biotechnology. This review critically evaluates current progress in micropropagation and regeneration systems in Passiflora spp. and examines the prospects of haploid and doubled haploid technologies as future breeding tools. Unlike previous reviews, which primarily focus on summarizing tissue culture protocols, this study integrates regeneration biology, developmental constraints, and emerging biotechnological approaches to provide a broader framework for research. Additionally, this review offers a comparative analysis of various regeneration systems across Passiflora species and highlights the challenges of genotype-dependent methods. By synthesizing recent advancements in haploid technology, it provides new insights into the potential for accelerating breeding programs in Passiflora, a field where robust protocols are still lacking.