Genome-wide characterization and expression of the APETALA2 (AP2) gene family in Glycine max L. reveal its importance in cold stress responses modulated by melatonin application.

Abstract

The soybean (Glycine max L.) is the world's most significant oilseed crop in terms of total production and international trade. Determining the genetic composition of soybeans is essential for identifying their characteristics, enhancing crop productivity and quality, and creating sustainable farming methods. AP2/ERF transcription factors regulate the responses against biotic and abiotic factors in the plants. However, little investigation of the AP2 family has been conducted in soybean. This study aims to introduce the expression of AP2 genes. A total of 50 nonredundant AP2 genes were analyzed by using a systematic genome-wide analysis. These genes were distributed on 19 chromosomes except chromosome number 20 that have no AP2 gene. Analysis of gene structure confirmed the presence of 2-10 introns in the AP2 family. In addition to the signature AP2 domain being completely conserved, 19 other domains were discovered to be conserved in a group-specific way. Synteny analysis expressed an intensive resemblance of orthologous regions between soybean and Arabidopsis thaliana. In-silico expression study based on transcriptome data demonstrated that soybean has differential expression of AP2 genes under cold stress. Additionally, during cold stress, most of these genes had the same patterns of expression but one gene (GLYMA_13G329700) is always upregulated irrespective of stress applied to soybean. This study revealed the characteristics of the AP2 gene family in soybean and provides valuable resources for further evolutionary and functional investigations of AP2 genes in this crop plant.