Activation of pepper basic PR-1 gene promoter during defense signaling to pathogen, abiotic and environmental stresses.

The basic PR-1 gene, CABPR1, accumulates in pepper leaf tissues during pathogen infection as well as after ethylene treatment. We isolated and functionally characterized the CABPR1 promoter region in tobacco leaves to identify the cis-acting regulatory sequences that are involved in CABPR1 gene expression. Constructs harboring the 5'-serially deleted CABPR1 promoter, which was fused to the beta-glucuronidase (GUS) gene, were evaluated for their promoter activity in the tobacco leaves. The CABPR1 promoter of 1670 bp in size was locally or systemically induced during a compatible interaction with Pseudomonas syringae pv. tabaci. The CABPR1 promoter also was differentially activated by treatment with ethylene, salicylic acid, nitric oxide, high salinity, drought and low temperature. The expression of the pepper transcription factors, CAZFP1 and CARAV1, activated the CABPR1 promoter. Analyses of a series of 5'-deletions of the CABPR1 promoter indicated that novel cis-acting elements essential for induction by pathogen and abiotic elicitors are localized in the region between -1670 bp and -1466 bp upstream from the translation start site. These results suggest that CABPR1 promoter is essential for regulating CABPR1 gene expression in response to pathogen, abiotic and environmental stresses, possibly by transactivating the CAZFP1 and CARAV1 transcription factors.