Subcellular localization of the Macadamia integrifolia Maiden & Betche zinc finger protein MiZFP17 and gene expression analysis under abiotic stress

C3H-type zinc finger protein genes function as key regulators of plant growth, development, and responses to abiotic stress. In this study, a C3H zinc finger protein gene, MiZFP17, was cloned from macadamia (Macadamia integrifolia Maiden & Betche) cultivar ‘ JW’ using RT-PCR, followed by bioinformatic characterization and subcellular localization. Spatial and stress-responsive expression patterns of MiZFP17 were quantified across macadamia organs and under multiple abiotic stress conditions using quantitative real-time PCR (qRT-PCR). Results showed that MiZFP17 contained three exons and two introns, and promoter analysis identified abundant cis-acting elements associated with phytohormone signaling, transcriptional regulation, and stress responsiveness. Structural features classified MiZFP17 as a tandem C3H zinc finger protein containing a coiled-coil region and two conserved ZnF-C3H domains. Transient expression of tobacco (Nicotiana benthamiana Domin) leaves demonstrated predominant nuclear localization. Expression profiling indicated broad transcription of MiZFP17 in roots, stems, leaves, flowers, small fruits, and kernels, with markedly elevated expression in small fruits and kernels relative to other tissues. Transcript abundance in leaves was significantly inhibited under low-temperature and drought stresses, whereas exposure to high salinity, elevated temperature, and herbicide treatment resulted in pronounced induction. These findings suggest that MiZFP17 encodes a nuclear-localized tandem C3H zinc finger protein with potential regulatory roles in macadamia organ development and adaptive responses to diverse abiotic stresses.