Bacterial wilt, as a bacterial disease, seriously impacts the growth of tobacco. The NAC transcription factors comprise one of the largest transcription factor families in plants, which play an important role in stress responses and bacterial disease resistance. Whereas little is known about tobacco NAC members in regulating the resistance to Ralstonia solanacearum.

In this study, the NtNAC060 gene was firstly cloned, then bioinformatics analysis, subcellular localization, transcriptional activation and function analysis were performed.

Results: 1) The NtNAC060 gene was cloned from tobacco genome and found to encode a typical NAC transcription factor; 2) The phylogenetic analysis revealed that NtNAC060 was divided into the ATAF1 subgroup; 3) The expression pattern analysis showed that NtNAC060 gene was expressed in tested tissues and induced by treatments of ABA, salt and pathogenic bacterium Ralstonia solanacearum; 4) The subcellular localization and transcriptional activation experiment convinced that the NtNAC060 serves as a transcriptional activator; 5) The overexpression of NtNAC060 gene could enhance the tolerance to both Ralstonia solanacearum and salt treatments in transgenic lines; 6) The expression levels of bacterial wilt progression related gene NtPR10 and salt stress responsive genes NtDREB1A were significantly induced in the NtNAC060 gene overexpression lines under pathogenic bacterium Ralstonia solanacearum and salt treatment, respectively; 7) The yeast-one hybrid assay indicated that NtNAC060 may regulate these responsive genes by binding their promoters directly.

Considering these results, the overexpression of the stress inducible NtNAC060 gene could enhance the bacterial wilt resistance and salt stress tolerance in tobacco by upregulating the stress related genes.