Chicory （Cichorium intybus L.） is a perennial forage extensively utilized in livestock production. The magnesium-dechelatase involved in chlorophyll degradation plays a pivotal rolein regulating chlorophyll breakdown and is a key factor in the control of stay-green traits of plants. Enhancing the stay-green phenotype is critical for improving chicory’s resilience to environmental stresses. In this study， two putative SGR （Stay-Green） genes were preliminarily identified in the chicory genome， and designated as CiSGR and CiSGRL based on their respective phylogenetic affiliations to the SGR and SGRL subfamilies. The proteins encoded by these genes were composed of 274 and 232 amino acids， respectively. Structural domain analysis revealed that both CiSGR and CiSGRL possessed chloroplast transit peptide domains， highly conserved SGR domains， and variable regions at the C-terminus. Cis-regulatory element analysis indicated that the promoters of CiSGR and CiSGRL contained light-responsive， hormone-related， and stress-inducible transcriptional elements. Subcellular localization assays demonstrated that CiSGR predominantly localized to chloroplasts and nuclei， whereas CiSGRL primarily resided in nuclei and cytoplasm. Tissue-specific expression profiling showed the highest transcript levels of both genes in stems and significant induction under six different abiotic stress conditions. This systematic identification and analysis of chicory SGR and SGRL genes provides a theoretical foundation for strategies aimed at improving chicory forage yield and quality.

Cichorium intybus  /  SGR gene family  /  Forage grass  /  Stress response