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

TL;DR

This study identifies JAZ genes in quinoa and shows that CqJAZ1 reduces the plant's ability to handle stress by affecting jasmonic acid signaling and antioxidant defenses.

Contribution

The study characterizes the JAZ gene family in quinoa and demonstrates the negative regulatory role of CqJAZ1 in abiotic stress responses.

Findings

CqJAZ1 is localized to the nucleus and its overexpression in Arabidopsis reduces stress tolerance.

CqJAZ1 overexpression leads to higher MDA levels and lower SOD and POD activities under stress.

CqJAZ1-overexpressing plants show reduced sensitivity to methyl jasmonate and lower endogenous JA accumulation.

Abstract

Jasmonic acid (JA) signaling plays a pivotal role in plant stress response, with Jasmonate ZIM-domain (JAZ) proteins acting as key transcriptional repressors. Quinoa (Chenopodium quinoa Willd.) is highly stress-tolerant, but its JAZ gene family remains poorly characterized. In this study, we identified 11 CqJAZ 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 CqJAZ genes to salt, drought, and saline-alkali stresses, among which CqJAZ1 was significantly down-regulated under all three conditions. Subcellular localization analysis indicated that CqJAZ1 is localized to the nucleus. Ectopic overexpression of CqJAZ1 in Arabidopsis thaliana 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.

Figures