Genome-wide identification and stress-responsive expression analysis of the Actin-Depolymerizing Factor (ADF) gene family in Avena sativa L

Oat (Avena sativa L.) is an important cereal crop globally, valued for both its grain and forage. Actin depolymerization factors (ADFs) are highly conserved eukaryotic proteins that facilitate remodeling of the actin cytoskeleton. Accumulating evidence indicates that ADFs play crucial roles in plant growth, development, and stress responses. Nevertheless, the AsADFs family has not yet been subjected to genome-wide identification in oat, a species with high abiotic stress tolerance. In this study, a total of 18 ADF genes (AsADF) were identified from the oat reference genome (Sang.v1.1) and mapped to 12 different chromosomes. Based on the phylogenetic analysis, these genes were classified into four groups, which was confirmed by their structure and the distribution of conserved motifs in the encoded proteins. Synteny analysis demonstrated strong relationships between oat and wheat ADFs. The promoters of most AsADFs family contain cis-elements associated with growth, development, and stress responses, suggesting their potential involvement in these biological processes. Subcellular localization prediction indicated that ADFs are mainly located in the cytoplasm, and this localization is consistent with their role in cytoskeletal maintenance. Analysis of qRT-PCR results indicated that most AsADFs exhibited differential expression patterns under diurnal rhythm and responded to various abiotic stresses. Among them, the expression levels of AsADF9, 13, and 14 from group B showed significant changes under all four abiotic stress conditions, suggesting their important roles in abiotic stress resistance. This study revealed that AsADF genes play crucial roles in oat’s response to various abiotic stresses. Notably, the expression of AsADF9, 13 and 14 was strongly induced under stress conditions, highlighting them as key candidates mediating oat’s stress response. In summary, the present study established a theoretical foundation for analyzing the molecular mechanism of stress resistance in oat and provides valuable insights for molecular breeding to enhance stress resistance.