Identification and Characterization of WOX Gene Family in Flax ( L.) and Its Role Under Abiotic Stress.

The WOX (WUSCHEL-related homeobox) gene family plays pivotal roles in plant growth, development, and responses to biotic/abiotic stresses. Flax ( L.), a globally important oilseed and fiber crop, lacks a comprehensive characterization of its WOX family. Here, 18 genes were systematically identified in the flax genome through bioinformatics analyses. Phylogenetic classification grouped these genes into three clades: Ancient, Intermediate, and WUS Clades, with members within the same clade exhibiting conserved exon-intron structures and motif compositions. Promoter analysis revealed abundant cis-acting elements associated with hormone responses (MeJA, abscisic acid) and abiotic stress adaptation (anaerobic induction, drought, low temperature). Segmental duplication events (nine gene pairs) contributed significantly to family expansion. Protein-protein interaction networks implicated several proteins in stress-responsive pathways. Expression profiling demonstrated that most genes were highly expressed in 5-day-post-anthesis (DPA) flowers and embryonic tissues. qRT-PCR validation further uncovered distinct expression patterns of genes under cold, drought, and salt stresses. This study established a foundational framework for leveraging genes to enhance stress tolerance in flax breeding and functional genomics.