Effect of LeERF1 and LeERF2 overexpression in the response to salinity of young tomato (Solanumlycopersicum cv. Micro-Tom) seedlings

Ethylene responsive factors (ERFs) are important transcriptional regulators involved in plant responses to abiotic stress. LeERF1 and LeERF2, two members of the ERF family in tomato (Solanum lycopersicum), have previously been cloned. In this study, we investigated the salt-stress tolerance of transgenic tomato overexpressing LeERF1 and LeERF2. The transgenic lines had longer roots than wild-type (WT) plants under salt stress conditions. Furthermore, we examined physiological and biochemical indexes in the plants and found that overexpression of LeERF1 and LeERF2 enhanced the release of chlorophyll and free proline, but decreased the malondialdehyde contents of the plants. Transgenic tomato displayed higher superoxide dismutase and guaiacol peroxidase activity than WT tomato under high salinity conditions. Moreover, quantitative RT-PCR analysis revealed that the expression levels of salt stress-related genes, including TAS14, HVA22, LHA1, PR5, and RBOHC, which were upregulated in the transgenic plants. Therefore, overexpression of LeERF1 and LeERF2 positively modulates the ethylene-mediated response to salt stress in tomato.