Differential expression of the AP2/EREBP gene family in the contrasting genotypes of maize provides insights of abiotic stress tolerance

Drought, heat, and salinity are the three most critical abiotic stresses that cause significant losses in agricultural production worldwide. Drought and heat stress cause the highest yield loss in maize. Transcription factors (TFs) of the AP2/EREBP family have been reported to provide tolerance against the various stresses in plants. The available genome database offers a valuable opportunity to identify and characterize the AP2/EREBP TFs in maize. A genome-wide survey was conducted, and 54 AP2/EREBP genes were identified in maize. Phylogenetic analysis divided the genes into different groups and showed their relation with other members. Further, physical mapping, localization study, gene structure, the conserved motif, and the analysis of the cis-regulatory elements were carried out for AP2/EREBP genes. We selected two contrasting genotypes for heat stress, BTM-14, and BTM-6, for further experiments based on pollen fertility and the number of pollen grains under heat stress. A total of 8 AP2/EREBP genes were selected based on in-silico transcriptome for additional validation in the leaf tissues of BTM-14 and BTM-6. The qRT-PCR analysis demonstrated differential expression of AP2/EREBP genes under drought and salt stresses. Since these genes were upregulated under drought and salinity stresses, they may be considered potential candidate genes for further functional validation and utilization in crop improvement programs for abiotic stress resistance. Overall, the present study provides new insights into the AP2/EREBP gene family at the genome level in maize, improving stress adaptation and tolerance in maize and other cereals crops. The study also suggested that the BTM-6 genotype could be a potential donor for heat and drought stress.