Genome-Wide Identification of the Maize ZmGeBP Gene Family and Functional Characterization of ZmGeBP8 in Stress Tolerance

Abstract

GLABROUS1 enhancer-binding protein (GeBP) family members are plant-specific transcription factors involved in growth, development, and environmental responses. However, the characteristics and stress-responsive patterns of this family in maize (Zea mays L.), particularly during seed aging and saline–alkali stress, remain insufficiently understood. We identified 19 ZmGeBP genes and classified their encoded proteins into four phylogenetic groups together with homologs from sorghum and rice. Duplication and synteny analyses showed that segmental duplication was the predominant duplication pattern detected in maize and that collinear relationships were retained among the three grasses. The ZmGeBP promoters contained cis-acting elements associated with development, light, phytohormone responses, and stress. RT-qPCR analysis of seven selected genes revealed temporal and genotype-dependent expression patterns during artificial seed aging and saline–alkali stress. Subcellular localization confirmed nuclear targeting of ZmGeBP8, and dual-luciferase reporter assays showed that ZmOCL13 reduced ZmGeBP8 promoter activity, suggesting a potential repressive effect. Overall, these findings elucidate the molecular features of maize ZmGeBP genes and establish a framework for validating their roles in stress resilience.