Abstract: 【Objective】 Cassava (Manihot esculenta) is an important tropical food crop that is prone to postharvest physiological deterioration (PPD), characterized by vascular discoloration, which severely affects its storage and utilization. bZIP transcription factors play crucial roles in responses to abiotic stress and regulation of antioxidant systems. This study aims to elucidate the function of the cassava MebZIP34 gene and explore its role in antioxidant regulation, thereby providing a theoretical basis and genetic resources for cassava postharvest preservation and stress-resistance breeding.【Methods】 The coding sequence of MebZIP34 was cloned from the storage roots of the cassava cultivar SC8. Bioinformatics analyses were performed, including protein structure, conserved motif identification, phylogenetic analysis, and promoter cis-element analysis. A plant overexpression vector was constructed and transiently expressed in cassava leaves to examine its regulatory effect on the downstream antioxidant gene MeMDAR1. Additionally, MebZIP34-overexpressing Arabidopsis transgenic lines were generated, and physiological indicators related to antioxidant capacity were assessed.【Results】The full-length CDS of MebZIP34 (975 bp) was successfully cloned, encoding a 324-amino-acid protein containing a typical bZIP domain, primarily composed of α-helices and random coils. Phylogenetic analysis revealed a close relationship between MebZIP34 and Arabidopsis AtbZIP13/40/12/66 as well as rice OsbZIP09/10/23. Promoter analysis indicated the presence of multiple cis-acting elements responsive to light, hormones, and stress. Transient expression assays showed that MebZIP34 significantly upregulated MeMDAR1 expression, enhanced SOD activity, and reduced MDA content. Similar expression and physiological changes were observed in MebZIP34-overexpressing Arabidopsis, suggesting that MebZIP34 positively regulates plant antioxidant capacity.【Conclusion】MebZIP34 is a bZIP transcription factor with conserved structural and functional characteristics that can enhance plant antioxidant capacity by regulating downstream gene expression, and it holds potential application value in cassava postharvest preservation and storage-resistance breeding.