J Integr Plant Biol. ›› 2010, Vol. 52 ›› Issue (10): 914-924.DOI: 10.1111/j.1744-7909.2010.00966.x

• Research Articles • Previous Articles     Next Articles

Characterization of a Novel Rice Metallothionein Gene Promoter: Its Tissue Specificity and Heavy Metal Responsiveness

Chun-Juan Dong, Yun Wang, Shi-Shi Yu and Jin-Yuan Liu*   

  1. Laboratory of Molecular Biology and MOE Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
  • Received:2010-02-26 Accepted:2010-04-28 Published:2010-10-01
  • About author:These authors contributed equally to this work.
    *Author for correspondence Tel: +86 10 6277 2243; Fax: +86 10 6278 8604; E-mail: liujy@mail.tsinghua.edu.cn

Abstract:

The rice (Oryza sativa L.) metallothionein gene OsMT-I-4b has previously been identified as a type I MT gene. To elucidate the regulatory mechanism involved in its tissue specificity and abiotic induction, we isolated a 1 730 bp fragment of the OsMT-I-4b promoter region. Histochemical β-glucuronidase (GUS) staining indicated a precise spacial and temporal expression pattern in transgenic Arabidopsis. Higher GUS activity was detected in the roots and the buds of flower stigmas, and relatively lower GUS staining in the shoots was restricted to the trichomes and hydathodes of leaves. No activity was observed in the stems and seeds. Additionally, in the root of transgenic plants, the promoter activity was highly upregulated by various environmental signals, such as abscisic acid, drought, dark, and heavy metals including Cu2+, Zn2+, Pb2+ and Al3+. Slight induction was observed in transgenic seedlings under salinity stress, or when treated with Co2+ and Cd2+. Promoter analysis of 5′-deletions revealed that the region −583/−1 was sufficient to drive strong GUS expression in the roots but not in the shoots. Furthermore, deletion analysis indicated important promoter regions containing different metal-responsive cis-elements that were responsible for responding to different heavy metals. Collectively, these findings provided important insight into the transcriptional regulation mechanisms of the OsMT-I-4b promoter, and the results also gave us some implications for the potential application of this promoter in plant genetic engineering.

Dong CJ, Wang Y, Yu SS, Liu JY (2010) Characterization of a novel rice metallothionein gene promoter: its tissue specificity and heavy metal responsiveness. J. Integr. Plant Biol. 52(10), 914–924.

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