Functional Characterization of the CpNAC1 Promoter and Gene from Chimonanthus praecox in Arabidopsis .

The NAC (NAM, ATAF, and CUC) gene family is one of the largest plant-specific transcription factor families. Its members have various biological functions that play important roles in regulating plant growth and development and in responding to biotic and abiotic stresses. However, their functions in woody plants are not fully understood. In this study, we isolated an NAC family member, the promoter and gene, from wintersweet. CpNAC1 was localized to the nucleus and showed transcriptional activation activity. qRT-PCR analyses revealed that the gene was expressed in almost all tissues tested, with the highest levels found in mature leaves and flower buds. Moreover, its expression was induced by various abiotic stresses and ABA treatment. Its expression patterns were further confirmed in () plants. Among all the transgenic lines, -D2 showed high GUS histochemical staining and activity in different tissues of . Furthermore, its GUS activity significantly increased in response to various abiotic stresses and ABA treatment. This may be related to the stress-related -elements, such as ABRE and MYB, which clustered in the -D2 segment, suggesting that -D2 is the core segment that responds to abiotic stresses and ABA. In addition, overexpressed plants had weaker osmosis tolerance than the wild-type plants, demonstrating that may negatively regulate the drought stress response in transgenic . Our results provide a foundation for further analyses of NAC family genes in wintersweet, and they broaden our knowledge of the roles that NAC family genes may play in woody plants.