Characterization of 4-Coumarate-CoA Ligase (4CL) Genes in Wheat Uncovers Ta4CL91’s Role in Drought and Salt Stress Adaptation

During the growth process, wheat (<i>Triticum aestivum</i> L.) is frequently subjected to abiotic stress. However, the mechanisms of abiotic stress in wheat are not yet well understood. In other crops, 4-coumarate-CoA ligases (4CLs) have been found to be involved in abiotic stress responses, but a systematic analysis of the response of <i>4CLs</i> to abiotic stress in wheat has not yet been conducted. Through a comprehensive genome-wide analysis, we identified 110 putative <i>4CL</i> genes in wheat. These genes were phylogenetically divided into distinct groups, with the authentic <i>4CLs</i> forming a separate branch and <i>4CL-like</i> genes being further categorized into six subgroups. Each clade exhibited conserved gene structures and motif compositions. Promoter analysis identified a variety of stress-responsive cis-regulatory elements within <i>Ta4CL</i> genes, indicating their potential involvement in stress regulation mechanisms. Expression profiling under drought and salt stress conditions identified specific <i>4CL</i> genes linked to stress tolerance. Notably, <i>Ta4CL91</i>, a member of the 4CL clade, showed strong dual responsiveness to both drought and salt stresses. Using virus-induced gene silencing (VIGS), we suppressed <i>Ta4CL91</i> expression and observed that the <i>Ta4CL91</i>-silenced plants became more sensitive to drought and salt stresses, highlighting <i>Ta4CL91</i>'s critical role in stress adaptation in wheat. This comprehensive study not only expands our understanding of the <i>4CL</i> gene family in wheat but also highlights the critical involvement of specific <i>4CL</i> members, such as <i>Ta4CL91</i>, in mediating this plant's resistance to abiotic stresses.