Transcriptome analysis of salt-tolerant adzuki bean in response to saline-alkaline stress

Ethylene-Response Factors (ERFs) proteins are members of a transcription factor family in plant growth and environmental stress responses, but the biological functions of ERF members in Adzuki bean (Vigna angularis var. angularis) remain unknown. In addition, it is unclear whether these proteins play roles in regulating responses to abiotic stressors. Here, we identified 47 ERF genes by analyzing the Adzuki bean genome. The result of whole-transcriptome analyses of saline-alkaline stress on Adzuki bean illustrates that 13 ERFs were induced in response to saline-alkaline stress. Promoter analysis showed that these saline-alkaline stress-inducible ERFs contained the LTR, DRE, MYB, ABRE, MYC, CGTCA-, and TGACG-motif cis-acting elements, important for responses to abiotic stress. VaERF3 was induced by NaHCO3, polyethylene glycol 6000, NaCl, and ABA, as determined by qRT-PCR. Overexpression of VaERF3 enhanced saline-alkaline stress in Arabidopsis with higher levels of proline accumulation and lower malondialdehyde and reactive oxygen species contents. Moreover, VaERF3 encoded a nuclear localized transcriptional activator and promoted stress-responsive genes expression. Collectively, the results are of great significance in elucidating the mechanisms of saline-alkaline stress responses in Adzuki bean.