A New AP2/ERF Transcription Factor from the Oil Plant Jatropha curcas Confers Salt and Drought Tolerance to Transgenic Tobacco

Jatropha curcas L. is a drought and salt-tolerant oil plant widely used for various purposes and has considerable potential as a diesel/kerosene substitute or extender. Understanding the molecular mechanisms underlie that the response to various biotic and abiotic stresses of this plant could be important to crop improvement efforts. Here, a new AP2/ERF-type transcription factor gene, named JcERF2, was isolated from the leaves of J. curcas. Sequence analysis showed that the JcERF2 gene contains a 759-bp open reading frame encoding a polypeptide of 252 amino acids. The predicted JcERF2 protein contained a conserved DNA-binding domain (the AP2/ERF domain) with 58 amino acids. The JcERF2 protein is highly homologous with other ERFs. JcERF2 was localized in the nucleus by analysis with a JcERF2-green fluorescent protein (GFP) fusion protein. Quantitative polymerase chain reaction (qPCR) analysis showed that JcERF2 was induced by drought, salt, abscisic acid, and ethylene. Overexpression of JcERF2 in transgenic tobacco plants enhanced the expression of biotic and abiotic stress-related genes, increased the accumulation of free proline and soluble carbohydrates, and conferred tolerance to drought and salt stresses compared to the wild type (WT). Taken together, the JcERF2 gene is a novel AP2/ERF transcription factor involved in plant response to environmental factors, which can be used as a potential candidate gene for genetic engineering of crops.