Cloning and preliminary functional analysis of AmNAC6 from Ammopiptanthus mongolicus

The full-length cDNA of a NAC transcription factor gene (AmNAC6) was cloned from Ammopiptanthus mongolicus (Maxim. ex Kom.) Cheng f., a plant with high tolerance to abiotic stresses, with the sequence characteristics, protein subcellular localization, and expression patterns of AmNAC6 then analyzed. Results showed that AmNAC6 encoded a 304 amino acid residue protein, which exhibited typical structural features of the NAC transcription factor family. Subcellular localization confirmed the nuclear distribution of the AmNAC6 protein. Expression analysis demonstrated that the transcription level of AmNAC6 in laboratory-cultured A. mongolicus seedlings changed during drought, salt, cold, and heat stress treatments, with the drought-induced expression more obvious than that under the other three treatments. In the young leaves of wild plants, the transcription levels were slightly lower in mid-autumn and early winter than in other seasons. The transcription level of the gene in young leaves was obviously lower than that in lateral roots, young branches, flower buds, and immature pods in spring. Moreover, the plant expression vector of AmNAC6 was successfully constructed, laying a foundation for further functional analyses.