Analysis of the promoter features of BpCUC2 in Betula platyphylla × Betula pendula

CUC2 encodes a NAC domain transcription factor required for establishing boundaries around plant organ primordia. It is also associated with the initiation of the shoot apical meristem. We cloned a 1497-bp BpCUC2 promoter fragment and constructed a pBpCUC2::LUC vector for birch transgenic. A quantitative real-time polymerase chain reaction (qRT-PCR) analysis of transgenic birch buds, leaves, stems, and roots revealed that luciferase (LUC) was most highly expressed in the buds. The pBpCUC2::LUC transgenic birch plants were treated with methyl jasmonate, indoleacetic acid, abscisic acid, or gibberellic acid3 for 2 h. The subsequent qRT-PCR analysis indicated that the transgenic birch tissues responded differently to the various hormones. Our results confirmed that BpCUC2 expression is influenced by hormones. The PLACE online tool revealed that the BpCUC2 promoter sequence contains several cis-acting elements. Furthermore, an auxin response element was used to screen transcription factors in a yeast one-hybrid assay. We identified three unique cDNA sequences, with complete open reading frames containing regulatory motifs, which were related to growth and development.