Unveiling the evolutionary and transcriptional landscape of ERF transcription factors in wheat genomes: a genome-wide comparative analysis

Ethylene response factors (ERFs), belonging to the AP2/ERF superfamily, play vital roles in plant growth, development, and stress responses. The evolutionary and expression features of the members of the ERF gene family have not yet been extensively analyzed through comprehensive comparative genomics across various diploid, tetraploid, and hexaploid wheat genomes. In this study, we identified a total of 2,967 ERF genes across one diploid, two tetraploid, and five hexaploid wheat genomes using the characteristics of conserved domains of ERF proteins. Phylogenetic analysis revealed that ERF genes clustered into two main groups. Analyses of expansion of the ERF gene family indicated that the members of IIIc and IX (sub)groups were observed to show the expansion in tetraploid and hexaploid wheat compared to diploid wheat. Tandem duplication was identified as a key mechanism for ERF gene family expansion, with varying proportions across different wheat genomes. Ancient evolutionary evidence was traced using Amborella trichopoda as a reference, revealing the retention of gene copies in both tetraploid and hexaploid wheat. Then, we analyzed the expression of ERF genes under salt stress in Triticum aestivum, identifying 86 consistently up-regulated and 14 down-regulated ERF genes, and reported the stress tolerant and disease resistant ERF genes in hexaploid wheat. These findings provide valuable insights into the evolutionary dynamics and functional features of ERF genes in wheat, paving the way for genetic breeding and molecular improvement of wheat species.