Peanut NAC Transcription Factor AhNAPa Negatively Regulates Salt Tolerance in Transgenic Arabidopsis

Soil salinity greatly impacts the planting area of cultivated peanut. It is necessary to breed salt-tolerant cultivars. However, few salt-resistant genes have been identified in peanut. Here, we reported the cloning of a peanut NAC transcription factor gene, AhNAPa, which was expressed ubiquitously and significantly upregulated after salt treatment. Furthermore, an AhNAPa-GFP fusion protein was found to be located in the nucleus, which indicated that AhNAPa might perform functions as a transcriptional activator in peanut. Under NaCl treatment, the root length of Arabidopsis plants overexpressing AhNAPa (AhNAPa-OX) were dramatically inhibited compared with the wild type (WT) lines, and the AhNAPa-OX adult plants became sensitive to salt stress. The expression levels of abiotic stress-responsive genes, SnRK2.2, NAC016, RD20, RD29B, and AREB1, significantly decreased in AhNAPa-OX plants, suggesting AhNAPa inhibited the ABA signaling pathway in response to salt stress. Taken together, these results suggest that the salt-inducible peanut transcription factor AhNAPa negatively regulated salt tolerance in transgenic Arabidopsis.