TaLACS Positively Regulates Wheat Resistance to Puccinia striiformis f. sp. tritici by Modulating ROS Accumulation

Wheat (Triticum aestivum L.) is a staple cereal crop in China, with its yield and quality closely linked to national food security. Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating airborne disease globally that inflicts severe yield losses due to its sudden outbreaks and rapid spread, highlighting an urgent need to identify wheat resistance genes against Pst. Long-chain acyl-CoA synthetases (LACSs) are key enzymes in lipid metabolism and play critical roles in plant stress tolerance, including defense responses against pathogens, across multiple plant species. However, their functions in the wheat-Pst interaction remain largely uncharacterized. Here, we cloned the wheat TaLACS gene, which localizes to the plasma membrane and is strongly induced during the early stages of Pst infection. Transient overexpression of TaLACS enhanced wheat resistance to Pst, as evidenced by a reduced disease index and Pst biomass, promotion of reactive oxygen species (ROS) burst at infection sites, and suppression of Pst hyphal growth. In contrast, virus-induced gene silencing-mediated knockdown of TaLACS impaired wheat basal resistance, resulting in increased disease severity and Pst proliferation, accompanied by a significant reduction in ROS accumulation. Transcriptome sequencing combined with quantitative real-time PCR validation revealed that TaLACS regulates multiple core defense signaling pathways, including plant-pathogen interaction, phenylpropanoid biosynthesis, and mitogen-activated protein kinase signaling. Collectively, our findings demonstrate that TaLACS positively modulates wheat resistance to Pst by promoting early ROS burst and regulating key defense-related pathways. This study uncovers a novel immune function of TaLACS in wheat and provides a valuable candidate gene for the molecular breeding of stripe rust-resistant wheat varieties, thereby contributing to the improvement of wheat disease resistance and the safeguarding of food security.