Genome-wide profiling of GRAS genes in flax ( L.) reveals as a key regulator of drought stress resistance.

GRAS genes are indispensable for modulating plant growth, developmental patterning, and adaptive responses to biotic and abiotic stress conditions. In this study, 99 genes were identified in the flax genome. Phylogenetic analysis classified them into 10 subfamilies: HAM, DELLA, DLT, SCL3, LAS, SCL4/7, SCR, SCL, SHR, and PAT1. Gene structure and motif analyses revealed that genes within the same clade exhibited conserved exon-intron organization and motif architectures. Promoter analysis showed that most genes contained cis-regulatory elements responsive to plant hormones (MeJA and abscisic acid) and abiotic stresses, including anaerobic induction, low temperature, and drought inducibility. MiRNA target prediction indicated that lus-miR395 is the primary regulatory miRNA for the gene family. Expression pattern analysis demonstrated that all family members were highly expressed in leaves and roots. qRT-PCR analysis further revealed that 10 genes were significantly upregulated under abiotic stresses (cold, drought, and salt), suggesting their involvement in antioxidant defense mechanisms. In , enhanced drought tolerance by scavenging reactive oxygen species (ROS) accumulation. Subcellular localization analysis demonstrated that was localized in the nucleus. This study provides new insights into the role of genes in flax stress tolerance and contributes to flax breeding and further functional research.