Identification and isolation of BZR transcription factor and screening of cell wall degradation marker genes based on machine learning in ripening kiwifruit

The BZR serves as a key transcription factor in brassinolide signal transduction, while ethylene is known to facilitate kiwifruit softening. However, the precise mechanism by which BZR mediates the interplay between ethylene and brassinolide in fruit softening remains unclear. In this study, we identified 8 BZR transcription factors within the kiwifruit genome and conducted an analysis of their expression profiles during fruit development, post-harvest storage, and in various tissues. Subsequently, the AdBZR1.1 and AdBZR1.4 which were induced by ethylene and brassinolide respectively, were screened and identified. Subcellular localization determined that AdBZR1.1 and AdBZR1.4 were localized the nucleus. Applying four machine learning methods, we further screened for cell wall degradation genes potentially involved in fruit softening. The dual-luciferase assays revealed that AdBZR1.1 and AdBZR1.4 do not directly regulate ethylene synthesis or the screened cell wall-related genes. However, transient overexpression analysis demonstrated that AdBZR1.1 and AdBZR1.4 can promote softening of the kiwifruit. The findings from our research provide a foundation for subsequent analysis of the transcriptional regulatory networks linked to AdBZR1.1 and AdBZR1.4. •Machine learning for predicting softening gene.•AdBZR1.1 and AdBZR1.4 regulated the softening in kiwifruit.•The expression of AdBZR1.1 and AdBZR1.4 were induced by ethylene and brassinolide.