Abstract
The phosphofructokinase (PFK) gene family plays a pivotal role in glycolysis and energy metabolism in plants. This study aimed to systematically characterize the PFK gene family in Arabidopsis thaliana at the genome-wide level and to investigate the function of AtPFK2 (ATP-dependent phosphofructokinase 2) in response to salt and drought stress. Through bioinformatics analysis, 11 AtPFK genes were identified. Phylogenetic analysis revealed that these PFK genes can be classified into two subfamilies: PFK and PFP. Notably, AtPFK2 possesses a unique structure, containing only a single intron, and its promoter is enriched with stress- and hormone-responsive elements, such as ABRE and MBS. T-DNA insertion mutants (pfk2) exhibited slightly shorter roots but slightly higher fresh weight under stress conditions, whereas Arabidopsis lines AtPFK2-overexpressing (OE-PFK2) showed increased stress sensitivity, with inhibited root and leaf growth, leaf wilting, reduced malondialdehyde and chlorophyll content, and enhanced accumulation of proline and soluble sugars. Weighted gene co-expression network analysis (WGCNA) identified 14 stress-related modules, from which six core genes-LBD41, TRP3, PP2-A3, SAUR10, IAA6, and JAZ1-were selected. These genes are involved in glycine metabolism and plant hormone signaling. The results of this study indicate that AtPFK2 mediates stress responses by regulating osmoregulatory substances and hormone signaling pathways, offering new insights into the mechanisms of stress resistance in crops.