Genome-Wide Identification and Expression Profiling of the ERF Gene Family in Medicago sativa L. Under Various Abiotic Stresses.

The AP2/ERF (APETALA2/ETHYLENE RESPONSE FACTOR) transcription factor represents one of the largest plant-specific transcriptional regulators in plants. ERF plays important roles in the regulation of various developmental processes and acts as a mediator in plant external stress responses. However, the research of the ERF gene family is still limited in alfalfa (Medicago sativa L.), one of the most important forage legume species in the world. In the present study, a total of 159 ERF genes were identified, and the phylogenetic reconstruction, classification, conserved motifs, signal peptide prediction, and expression patterns under salt, drought, and low-temperature stresses of these ERF genes were comprehensively analyzed. The ERF genes family in alfalfa could be classified into 10 groups and predicted to be strongly homologous. Based on the structure and functions relationships, the III and IV subfamilies were more likely to play functions in abiotic stresses and 18 MsERF genes were selected for further quantitative real-time PCR validation in different stresses treatment. The results showed that all these MsERF genes were upregulated under three stresses except MsERF008. This study identified the possibility of abiotic tolerance candidate genes playing various roles in stress resistance at the whole-genome level, which would provide primary understanding for exploring ERF-mediated tolerance in alfalfa.