Genome-Wide Identification of NAC Transcription Factors in Chimonanthus praecox and Transgene CpNAC30 Affects Salt and Drought Tolerance in Arabidopsis

Abstract

NAC (NAM, ATAF1/2, and CUC2) transcription factors regulate plant growth and development and response to various stresses. However, there is still limited insight into the NAC family in Chimonanthus praecox. This study performed a genome-wide characterization of the NAC transcription factor family members in C. praecox. A total of 105 NAC family members were identified from the C. praecox genome. The phylogenetic tree categorized the CpNACs into nine groups and the accuracy of this classification was confirmed by the analysis results of conserved motifs, conserved domain, and gene structure. Cis-acting element analysis revealed that the promoters of CpNACs were abundant in elements responsive to various hormones and stresses, implying the functional diversity and complexity of CpNACs. Furthermore, we investigated the function of the CpNAC30. The expression level of CpNAC30 could be significantly induced by abiotic stress and the CpNAC30 was the highest expressed in mature leaves of C. praecox. Overexpression of CpNAC30 reduced salt stress tolerance of transgenic Arabidopsis. Nevertheless, the drought stress tolerance of transgenic plants was enhanced. This study lays a foundation for further understanding the function of CpNACs genes and provides insights for abiotic stress tolerance breeding of C. praecox and other woody plants.