Poster: Late and Moved Abstracts

Abs # 982: A Novel Oxidative Stress-inducible Peroxidase Promoter from Sweetpotato

Presenter:	Ryu, Sun-Hwa , shryu21@kribb.re.kr
Authors	Ryu, Sun-Hwa  (A)   Park, Soo-Young  (A)   Kim, Yun-Hee  (A)   Kwon, Suk-Yoon  (A)   Kwak, Sang-Soo  (A)
Affiliations:	(A): Korea Research Institue of Bioscience and Biotechonology

We have cloned 6 guaiacol-type peroxidase (POD) cDNAs from suspension cultures of sweetpotato (Ipomoea batatas (L.) Lam.) in the project. Among them, swpa4 was most highly induced by both abiotic and biotic stress, suggesting that this gene was regulated by a multiple stress-inducible promoter (Park et al., 2003). A SWPA4 genomic clone consisted of 2,433 bp of 5กฏ-upstream sequence from the translation start site, two introns (115 bp and 168 bp), and a 1,229 bp coding region. Employing a transient expression assay in tobacco BY-2 protoplasts, 2.4 kb promoter and five progressive deletion mutants, -1934, -1467, -1199, -818 and -433, were fused to the GUS gene and their GUS activities were analyzed. Each deletion mutants showed diverse GUS activities. The -1934 bp and -433 bp deletion mutants showed about 8 and 4.5 times higher GUS expression than the CaMV 35S promoter, respectively. Analysis of further deletion mutants of -433 bp promoter showed that the removal of the region between -237 and -177 reduced GUS activity to the level of CaMV35S, indicating the presence of positive cis-elements in relation to stress are located in this region. In addition, Transgenic plants under the control of -2433, -1467 or -433 promoters were generated to survey the vivo activity of each promoter in response to stress. Interestingly, GUS activity was strongly expressed in stem and root tissues of young seedlings under the control of -1467 bp promoter. Any GUS activities in transgenic plants were not detected in leaves but its activities were strongly induced by treatment of wounding, H₂O₂, NaCl, GA, SA, and IAA.