Responses of the Lipoxygenase Gene Family to Drought Stress in Broomcorn Millet (Panicum miliaceum L.)

<b>Background:</b> Broomcorn millet (<i>Panicum miliaceum</i> L.), a drought-tolerant C4 crop, is crucial for agricultural resilience in arid regions. Lipoxygenases (LOXs), key enzymes in plant stress responses, have not been studied in broomcorn millet. This study aimed to identify <i>LOX</i> genes in broomcorn millet and elucidate their role in drought tolerance. <b>Methods:</b> We employed bioinformatics and physiological analyses to identify <i>LOX</i> genes in broomcorn millet. Expression profiles were assessed in different organs, and drought stress responses were evaluated in tolerant (HSZ, YXDHM) and sensitive (YS10) varieties. Antioxidant enzyme activities (SOD, POD, CAT) and malondialdehyde (MDA) levels were measured. <b>Results:</b> Twelve <i>LOX</i> genes were identified, classified into three subfamilies, and mapped across seven chromosomes. These genes contained stress-responsive cis-elements and showed organ-specific expression, with <i>PmLOX5</i> exhibiting no detectable expression. Under drought stress, tolerant varieties showed elevated antioxidant activities and reduced MDA accumulation. <i>PmLOX2</i>, a homolog of Arabidopsis <i>AtLOX1</i>/<i>AtLOX5</i>, was significantly induced in tolerant varieties, correlating with enhanced antioxidant capacity and reduced oxidative damage. <b>Conclusions:</b><i>PmLOX</i> genes, particularly <i>PmLOX2</i>, play a pivotal role in drought tolerance by modulating ROS scavenging and membrane protection. This study provides a foundation for leveraging <i>LOX</i> genes to improve drought resilience in broomcorn millet and related crops.