Cloning and analysis of the ascorbate peroxidase gene promoter from Brassica napus

Abstract

Ascorbate peroxidase (APX) is known to catalyze the reduction of H₂O₂ to water and enhance plants’ tolerance in stress environment. An ascorbate peroxidase protein (BnAPX) was previously isolated from Brassica napus in our laboratory and it was located in the chloroplast. In order to clarify the physiological function of BnAPX in plant response to photooxidative stress, 1562 bp upstream sequence of BnAPX was isolated by genomic walking and searched for cis-element by PROMOTER SCAN software and PLANTCARE website. Many light-responsive cis-elements were revealed in this prediction. Promoter activity analysis of this sequence was operated by transient expression in B. napus protoplasts. Results of promoter deletion analysis indicated that the core promoter element lied in 0.3 kb of BnAPX 5’-flanking region. Moreover, our data showed that promoter of BnAPX could be activated by light.

Key words: BnAPX, H2O₂, promoter analysis, transient expression, genomic walking, 5’-flanking region.