title: Characterization of the glyoxalase 1 gene TcGLX1 in the metal hyperaccumulator plant Thlaspi caerulescens.
abstract: Stress tolerance is currently one of the major research topics in plant biology because of the challenges posed by changing climate and increasing demand to grow crop plants in marginal soils. Increased Zn tolerance and accumulation has been reported in tobacco expressing the glyoxalase 1-encoding gene from Brassica juncea. Previous studies in our laboratory showed some Zn tolerance-correlated differences in the levels of glyoxalase 1-like protein among accessions of Zn hyperaccumulator Thlaspi caerulescens. We have now isolated the corresponding gene (named here TcGLX1), including ca. 570 bp of core and proximal promoter region. The predicted protein contains three glyoxalase 1 motifs and several putative sites for post-translational modification. In silico analysis predicted a number of cis-acting elements related to stress. The expression of TcGLX1 was not responsive to Zn. There was no correlation between the levels of TcGLX1 expression and the degrees of Zn tolerance or accumulation among T. caerulescens accessions nor was there co-segregation of TcGLX1 expression with Zn tolerance or Zn accumulation among F3 lines derived from crosses between plants from accessions with contrasting phenotypes for these properties. No phenotype was observed in an A. thaliana T-DNA insertion line for the closest A. thaliana homolog of TcGLX1, ATGLX1. These results suggest that glyoxalase 1 or at least the particular isoform studied here is not a major determinant of Zn tolerance in the Zn hyperaccumulator plant T. caerulescens. In addition, ATGLX1 is not essential for normal Zn tolerance in the non-tolerant, non-accumulator plant A. thaliana. Possible explanations for the apparent discrepancy between this and previous studies are discussed.
authors.affiliation: Department of Biosciences, University of Eastern Finland, Kuopio Campus, P.O. Box 1627, 70211 Kuopio, Finland. marjo.tuomainen@uef.fi
authors.forename: Marjo
authors.initials: M
authors.lastname: Tuomainen
authors.forename: Viivi
authors.initials: V
authors.lastname: Ahonen
authors.forename: Sirpa O
authors.initials: SO
authors.lastname: Kärenlampi
authors.forename: Henk
authors.initials: H
authors.lastname: Schat
authors.forename: Tanja
authors.initials: T
authors.lastname: Paasela
authors.forename: Algirdas
authors.initials: A
authors.lastname: Svanys
authors.forename: Saara
authors.initials: S
authors.lastname: Tuohimetsä
authors.forename: Sirpa
authors.initials: S
authors.lastname: Peräniemi
authors.forename: Arja
authors.initials: A
authors.lastname: Tervahauta
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D001483:Base Sequence; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007791:Lactoylglutathione Lyase / Q000235:genetics* / Q000378:metabolism; D019216:Metals, Heavy / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020539:Sequence Analysis, Protein; D013312:Stress, Physiological / Q000235:genetics; D031227:Thlaspi / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D015032:Zinc / Q000378:metabolism
chemical_list: D019216:Metals, Heavy; D010940:Plant Proteins; D007791:Lactoylglutathione Lyase; D015032:Zinc