Genome-Wide Identification of the JAZ Family in Quinoa and the Negative Regulatory Role of CqJAZ1 in Abiotic Stress Responses

Jasmonic acid (JA) signaling plays a pivotal role in plant stress response, with Jasmonate ZIM-domain (JAZ) proteins acting as key transcriptional repressors. Quinoa (<i>Chenopodium quinoa</i> Willd.) is highly stress-tolerant, but its <i>JAZ</i> gene family remains poorly characterized. In this study, we identified 11 <i>CqJAZ</i> genes in the quinoa genome and systematically analyzed their phylogenetic relationships, gene structures, conserved motifs, and cis-acting elements in their promoters. Expression profiling revealed distinct response patterns of <i>CqJAZ</i> genes to salt, drought, and saline-alkali stresses, among which <i>CqJAZ1</i> was significantly down-regulated under all three conditions. Subcellular localization analysis indicated that CqJAZ1 is localized to the nucleus. Ectopic overexpression of <i>CqJAZ1</i> in <i>Arabidopsis thaliana</i> inhibited root growth and reduced survival rates under salt, saline-alkali, and osmotic stresses. Physiologically, CqJAZ1-overexpressing lines had elevated malondialdehyde (MDA), decreased superoxide dismutase (SOD) and peroxidase (POD) activities, and reduced endogenous JA accumulation under stress conditions. Furthermore, they showed reduced methyl jasmonate (MeJA) sensitivity. Collectively, CqJAZ1 negatively regulates quinoa stress tolerance by modulating JA homeostasis and compromising antioxidant defense capacity, shedding light on quinoa's JA signaling and stress-resistance mechanisms.