Genome-wide identification and expression analysis of the Pisum sativum (L.) APETALA2/ethylene-responsive factor (AP2/ERF) gene family reveals functions in drought and cold stresses

AP2/ERF (APETALA2/Ethylene Response Factor) is a family of transcription factors that play essential roles in regulating gene expression in response to various environmental stimuli, including biotic and abiotic stresses, hormone signaling, and developmental processes. Pisum sativum (L.), commonly known as garden pea, is a winter crop sensitive to high temperatures and can also be affected by extreme cold and drought conditions. This study performed a genome-wide analysis of AP2/ERF genes and identified 153 AP2/ERF genes in P. sativum. Based on the conserved AP2/ERF domain and sequence homology, they were classified into AP2 (APETALA2), ERF (Ethylene Response Factor), DREB (Dehydration responsive element-binding), RAV (Related to Abscisic Acid Insensitive 3/ Viviparous 1) and Soloist subfamily. The DREB and ERF subfamily were further divided into groups A1-6 and B1-B6. Tandem and segmental duplication events were more frequent in the ERF subfamily, which can have important implications for their evolution and functional diversification. Under cold stress, the expression of DREB1A was highly induced in leaves, whereas DREB1B was suppressed. Similarly, the DREB2A, DREB2C, DREB2E, and DREB2F were induced in leaves under drought stress. The putative target genes of AP2/ERF transcription factors are highly diversified, suggesting that they play essential roles in various physiological responses in plants, including responses to biotic and abiotic stresses as well as developmental processes. Thus, this study of AP2/ERF genes and their functions provides valuable insight into how P. sativum responds to different environmental conditions, including cold and drought stresses.