Functional Analysis of Zinc Finger Protein Transcription Factor ZmZFP69 Under Low-Temperature Stress at Maize Seedling Stage

Maize (Zea mays L.) seedlings are highly susceptible to low-temperature stress, which significantly impacts maize yield and quality. A zinc finger protein transcription factor (ZmZFP69) mutant and a control (B73) maize inbred line were subjected to low-temperature treatment, and changes in the phenotypic characteristics, hormone levels, and other indicators before and after the treatment were systematically identified. Subsequently, a combined RNA-seq and DAP-seq analysis was conducted to explore the influence of ZmZFP69 on the promoters of downstream genes. Finally, the proteins interacting with ZmZFP69 were examined using InterProDesign combined with BiFC and subcellular localization. The zmzfp69 homozygous mutant maize inbred line exhibited enhanced low-temperature tolerance compared to the control. RNA-seq and DAP-seq analyses revealed that ZmZFP69 binds to the ZmAOX2 gene promoter, significantly suppressing its expression. The interaction between ZmZFP69 and the downstream protein ZmBG6 was confirmed by InterProDesign, subcellular localization, and BiFC assays. ZmZFP69 negatively regulates maize seedling low-temperature tolerance by inhibiting ZmAOX2 expression and interacting with ZmBG6.