Molecular characterization of glyoxalase-I from a higher plant; upregulation by stress

• Published in: Plant molecular biology Vol. 29; no. 6; p. 1223
• Main Authors: Espartero, J. (Instituto de Recursos Naturales y Agrobiologia CSIC, Sevilla (Spain)), Sanchez-Aguayo, I, Pardo, J.M
• Format: Journal Article
• Language: English
• Published: Netherlands 01.12.1995
• Subjects: Amino Acid Sequence; Bacteria - enzymology; Base Sequence; Cloning, Molecular; DNA, Complementary; ENZIMAS; ENZYME; ENZYMES; ESTRES; EXPRESION GENICA; EXPRESSION DES GENES; GENE EXPRESSION; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Humans; Immunohistochemistry; Lactoylglutathione Lyase - biosynthesis; Lactoylglutathione Lyase - chemistry; Lactoylglutathione Lyase - genetics; LYCOPERSICON ESCULENTUM; Lycopersicon esculentum - enzymology; Molecular Sequence Data; Recombinant Proteins - biosynthesis; Recombinant Proteins - chemistry; Saccharomyces cerevisiae; SALINIDAD; SALINITE; SALINITY; Sequence Homology, Amino Acid; STRESS; Stress, Physiological
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/bf00020464

A cDNA, GLX1, encoding glyoxalase-I was isolated by differential screening of salt-induced genes in tomato. Glyoxalases-I and -II are ubiquitous enzymes whose functions are not clearly understood. They may serve to detoxify methylglyoxal produced from triosephosphates in all cells. The protein encoded by GLX1 shared 49.4% and 58.5% identity with glyoxalase-I isolated from bacteria and human, respectively. Furthermore, yeast cells expressing GLX1 showed a glyoxalase-I specific activity 20-fold higher than non-transformed cells. Both GLX1 mRNA and glyoxalase-I polypeptide levels increased 2- to 3-fold in roots, stems and leaves of plants treated with either NaCl, mannitol, or abscisic acid. Immunohistochemical localization indicated that glyoxalase-I was expressed in all cell types, with preferential accumulation in phloem sieve elements. This expression pattern was not appreciably altered by salt-stress. We suggest that the increased expression of glyoxalase-I may be linked to a higher demand for ATP generation and to enhanced glycolysis in salt-stressed plants.