Molecular cloning of a putative Acanthus ebracteatus - 9-cis-epoxycarotenoid deoxygenase (AeNCED) and its overexpression
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J. Crop Sci. Biotech. 2014 (December) 17 (4) : 239 ~ 246 DOI No. 10.1007/s12892-014-0006-4 RESEARCH ARTICLE
Molecular Cloning of a Putative Acanthus ebracteatus- 9-cisepoxycarotenoid deoxygenase (AeNCED) and its Overexpression in Rice Shahanaz Sultana1, Veronika
, Chai-Ling Ho1, Suhaimi Napis1 , Parameswari Namasivayam1, *
2
Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor D E, Malaysia 2 Laboratory of Growth Regulators, Palacky University & UEB AV CR, Slechtitelu 11, 78371 Olomouc-Holice, Czech Republic 1
Received : January 14, 2014 / Revised: July 22, 2014 / Accepted: September 19, 2014 Ⓒ Korean Society of Crop Science and Springer 2014
Abstract 9-Cis-epoxycarotenoid dioxygenase (NCED) is an important enzyme which catalyzes the oxidative cleavage of abscisic acid (ABA), a plant growth regulator which plays a vital role in stress tolerance. In this study, a cDNA sequence encoding NCED from a mangrove plant (Acanthus ebracteatus) was analyzed and overexpressed in rice. Analysis of the deduced amino acid sequence of AeNCED revealed an open reading frame of 1,638 bp encoding a protein of 545 amino acids, with a 123 bp 5’-untranslated region (UTR) and a 259 bp 3’-UTR. The deduced amino acid sequence of AeNCED is more than 80% identical to the amino acid sequences of carotenoid cleavage dioxygenase from carrot, tomato, and coffee. The RNA encoding AeNCED was detected in transgenic rice (Oryza sativa cv. BRRI dhan29) plants overexpressing this cDNA. These plants only showed significantly higher tolerance to salinity at germination and better performance at seedling stages. The levels of ABA in transgenic rice seedlings overexpressing AeNCED treated with 100 mM NaCl for 24 hours were higher than those of untransformed plants. However, a higher level of dihydrophaseic acid (DPA) and ABA glucose ester (ABA-GE) were also observed in these transgenic plants suggesting that rapid degradation of ABA through a self-regulation mechanism. Key words : 9-cis-epoxycarotenoid dioxygenase, overexpression, rice, salt tolerance, sequence analysis
Introduction Soil salinity is one of the major limiting factors that affect crop productivity. Abscisic acid (ABA), a plant growth regulator, was proposed to be a primary signal which operates as a mediator between the adverse environment and plant responses against stresses (Gomez Cadenas et al. 2000; Mehouachi et al. 2005). The regulation of ABA is one of the most important focal points of research on plant responses to drought and salt stresses. ABA is derived from C40-cisepoxycarotenoids via a multiple- step biosynthetic pathway (Cutler and Krochko 1999). The cleavage of 9-cis-epoxyParameswari Namasivayam (
) E-mail: [email protected] Tel: +60389468344 / Fax:+60389467510
The Korean Society of Crop Science
carotenoids to apocarotenoid (C25) and xanthoxin (C15), the precursor of ABA is catalized by 9-cis-epoxycarotenoid dioxygenase (NCED) (Schwartz et al. 1997). Xanthoxi
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