Regular Article

Cell Research (2001) 11, 187–193. doi:10.1038/sj.cr.7290085

Isolation of a choline monooxygenase cDNA clone from Amaranthus tricolor and its expressions under stress conditions

Yu Ling MENG1, Yu Mei WANG2, Da Bing ZHANG3 and Naosuke NII1

  1. 1Faculty of Agriculture, Meijo University, Tempaku-ku, Nagoya, Aichi, 468-8502 Japan
  2. 2Yingdong College of Biotechnology, Shaoguan University, Datang Road, Shaoguan 512005, China.
  3. 3Agro-Biotech Center of Shanghai Academy of Agricultural Sciences, Shanghai Key Laboratory of genetic breeding, 2901 Beidi Road, Shanghai 201106, China.

Correspondence: Naosuke NII, Tel: ++81-52-832-1151 (6057), e-mail: nii@meijo-u.ac.jp

Received 29 December 2000; Revised 27 June 2001; Accepted 4 July 2001.

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Abstract

Plants synthesize the osmoprotectant glycine betaine (GB) via cholineright arrow betaine aldehyderight arrowglycine betaine1. Two enzymes are involved in the pathway, choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH). A full length CMO cDNA (1,643bp) was cloned from Amaranthus tricolor. The open reading frame encoded a 442-amino acid polypeptide, which showed 69% identity with CMOs in Spinacia oleracea L. and Beta vulgaris L. DNA gel blot analysis indicated the presence of one copy of CMO gene in the A. tricolor genome. The expressions of CMO and BADH proteins in A.tricolor leaves significantly increased under salinization, drought and heat stress (42°C), as determined by immunoblot analysis, but did not respond to cold stress (4°C), or exogenous ABA application. The increase of GB content in leaves was parallel to CMO and BADH contents.

Keywords:

Amaranthus tricolor, betaine aldehyde dehydrogenase (BADH), choline monooxygenase (CMO), glycine betaine (GB), stress

Abbreviations:

BADH, betaine aldehyde dehydrogenase; CMO, choline monooxygenase; GB, glycine betaine; ABA, abscisic acid; PMSF, phenylmethyl sulfonylfluoride; NEM, N-ethylmaleimide; PAGE, polyacrylamide gel electrophoresis; bp, base pair; kb, kilobase; kDa, kilodalton

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