Background: Cymbidium goeringii, one of China’s traditional and valuable orchids, possesses significant ornamental and economic value. However, it is relatively sensitive to low temperature and other abiotic stresses, which severely restrict its application in landscaping and industrial development. WRKY transcription factors play important roles in plant responses to abiotic stresses, yet related research in C. goeringii remains limited. Methods: In this study, based on transcriptome data of C. goeringii under four different stresses, we identified and cloned the WRKY transcription factor gene CgWRKY53. Through bioinformatics analysis, quantitative real-time PCR, and heterologous transformation in Arabidopsis thaliana, we systematically investigated its structural characteristics, expression patterns, and function under cold stress. Results: The full-length CDS of CgWRKY53 is 1080 bp, encoding a protein of 359 amino acids with a molecular weight of 39.95 kDa. Group III subfamily of the WRKY family, possessing the conserved WRKYGQK domain and a C2HC-type zinc finger motif. CgWRKY53 is expressed in roots, pseudobulbs, leaves, and flowers of C. goeringii, with the highest expression observed in flowers. Under cold, heat, waterlogging, and ABA treatments, CgWRKY53 displayed significant changes in expression, with the most pronounced response occurring under cold stress, where its expression was significantly upregulated. Homozygous transgenic A. thaliana lines overexpressing CgWRKY53 exhibited dwarfed stature, with smaller and deformed leaves and notably shorter roots compared to wild-type plants. The overexpression lines also showed cold-sensitive phenotypes under low-temperature stress, and the expression of several cold-responsive genes was suppressed, suggesting that CgWRKY53 may act as a negative regulator in the response to cold stress. Conclusions: These results identify CgWRKY53 as a negative regulator of cold stress response in C. goeringii. This study provides important genetic resources and theoretical foundations for molecular breeding of stress-resistant orchids.
Ma et al. (Thu,) studied this question.