Improved drought and salt tolerance in transgenic Arabidopsis overexpressing a NAC transcriptional factor from Arachis hypogaea.

The NAC (NAM, ATAF, and CUC) proteins share a highly conserved NAC domain and constitute a large family of plant-specific transcriptional factors. We have isolated a drought-induced NAC gene from Arachis hypogaea, named AhNAC2 (Arachis hypogaea NAC2) but its specific role remains unknown. In this study, we found that transgenic Arabidopsis overexpressing AhNAC2 lines were hypersensitive to ABA in root growth, seed germination, and stomatal closure compared to wild type Arabidopsis. The transgenic lines exhibited enhanced tolerance to drought and salinity stress, and the expression levels of 12 stress-related genes in the AhNAC2 transformed plants were higher than in wild type Arabidopsis. These results indicate that AhNAC2 is a major player in the NAC gene family involved in ABA signaling. Its role as a candidate gene for engineering drought and salt tolerance in cultivated plants is discussed.