Identification and deletion analysis of the promoter of the pepper SAR8.2 gene activated by bacterial infection and abiotic stresses

Abstract

The pepper SAR8.2 gene, CASAR82A, was locally and systemically induced in pepper plants which had been infected by Xanthomonas campestris pv. vesicatoria or by Pseudomonas fluorescens. The DNA 1,283 bp sequence upstream of the CASAR82A gene was assessed with regard to the activity of the CASAR82A promoter fused to the beta-glucuronidase (GUS) reporter gene, via an Agrobacterium-mediated transient expression assay. In tobacco leaves which transiently expressed the -831 bp CASAR82A promoter, GUS activity was locally and systemically induced by Pseudomonas syringae pv. tabaci. GUS activity, which was driven by the -831 promoter, was also differentially activated in the leaves as the result of treatment with salicylic acid, ethylene, methyl jasmonate, abscisic acid, NaCl, and low temperatures. The -831 bp sequence upstream of the CASAR82A gene elicited full promoter activity in response to pathogen infection, abiotic elicitors, and environmental stresses. The expression of the pepper transcription factor, CARAV1, was shown to activate the CASAR82A promoter. Analyses of a series of 5'-deletions of the CASAR82A promoter revealed that novel cis-acting elements necessary for the induction of gene expression as the result of exposure to pathogen and abiotic elicitors appear to be localized in the promoter region between -831 and -759 bp.