Functional analysis of the promoter of the pepper pathogen-induced gene, CAPIP2, during bacterial infection and abiotic stresses

Promoter is a region of DNA to which transcription factor binds before initiating the transcription of DNA into RNA. The pepper pathogen-induced protein gene, CAPIP2, was locally or systemically induced in pepper plants infected by Xanthomonas campestris pv. vesicatoria. In this study, we isolated and transiently characterized the CAPIP2 promoter in tobacco leaves to identify the cis-acting regulatory sequences involved in CAPIP2 gene expression. The 991-bp DNA sequence upstream of the CAPIP2 gene was assessed for the activity of the CAPIP2 promoter fused to the β-glucuronidase (GUS) reporter gene, via an Agrobacterium-mediated transient expression assay. Several cis-acting elements, including GT1, MYB, RAV, and W-box, resided within the genomic sequence upstream of the CAPIP2 gene. The activation of the CAPIP2 promoter was induced by Pseudomonas syringae pv. tabaci, salicylic acid, methyl jasmonate and abscisic acid, NaCl and cold stress. The expression of the pepper transcription factors, CARAV1 and CAZFP1, was shown to activate the CAPIP2 promoter. Analysis of a series of 5′-deletions of the CAPIP2 promoter suggests that novel cis-acting elements necessary to induce gene expression by pathogens and environmental stresses are specifically localized in the CAPIP2 promoter region.