Characterization of a non-specific Lipid Transfer Protein (ns-LTP) promoter from poplar (Populus alba × P. glandulosa)

In order to study genetic engineering in trees, the characterization of genes and promoters from trees is necessary. We isolated the promoter region (867 bp) of Pagns-LTP from poplar (P. alba P. glandulosa) and characterized its activity in transgenic poplar plants using a -glucuronidase (GUS) reporter gene. High-level expression of the Pagns-LTP transcript was found in poplar roots, while comparatively low-level expression was found in the young leaves. Pagns-LTP mRNA was not detected in other poplar tissues. Additionally, transgenic poplar plants that contained a Pagns-LTP promoter fused to a GUS reporter gene, displayed tissue-specific GUS enzyme activity localized in root tissue. In silico analysis of the Pagns-LTP promoter sequence reveals the presence of several cis-regulatory elements responsive to phytohormones, biotic and abiotic stresses, as well as those regulating tissue-specific expression. These results demonstrate that the Pagns-LTP promoter has tissue-specific expression activity in poplar roots and leaves that may be involved in organ development and plant resistance to various stresses. Therefore, we anticipate that the Pagns-LTP promoter would be a useful tool to genetically optimize woody plants for functional genomics.