Comprehensive Analysis of Faba Bean <i>AP2/ERF</i> Genes Suggests Potential Roles of <i>VfAP2‐1</i> and <i>VfERF‐99</i> in Abiotic and Biotic Stress Responses

The AP2/ERFs not only participate in regulating signal networks, but they also play important roles in the process of plant growth and stress response. However, systematic research of AP2/ERF in Vicia faba is lacking. In this study, VfAP2/ERF was systematically identified and their characteristics were comprehensively analyzed. In total, 145 VfAP2/ERFs were identified, which were unevenly distributed across six chromosomes, and according to phylogenetic relationships, VfAP2/ERFs could be classified into five subgroups. Cis-elements analysis showed that VfAP2/ERF promoters harbored numerous elements functionally relating to light response, plant hormone, abiotic stress response, and plant growth and development response. Expression profiling analysis indicated that VfAP2/ERFs were broadly expressed during growth and development, and were responsive to drought and salt stresses. RT-qPCR revealed that six VfAP2/ERF genes were upregulated under drought and salt stress. Inoculation assay showed that VfAP2-1 and VfERF-99 could enhance resistance to pathogens. Further research shows that VfAP2-1 and VfERF-99 positively influence ROS homeostasis, resulting in the accumulation of H₂O₂ and O₂ ^- under abiotic and biotic stresses, which inhibited the colonization of pathogens. Additionally, VfAP2-1 and VfERF-99 could significantly increase the content of chlorophyll a, carotenoids, and total chlorophyll, suggesting their possible roles in promoting photosynthesis. This study comprehensively analyzed VfAP2/ERFs and preliminarily explored the function of VfAP2-1 and VfERF-99 in biotic/abiotic stresses and photosynthesis, which laid the foundation for deciphering their functional mechanisms.