title: Modification of intracellular levels of glutathione-dependent formaldehyde dehydrogenase alters glutathione homeostasis and root development.
abstract: Glutathione (GSH)-dependent formaldehyde dehydrogenase (FALDH) is a highly conserved medium-chain dehydrogenase reductase and the main enzyme that metabolizes intracellular formaldehyde in eukaryotes. It has been recently shown that it exhibits a strong S-nitrosoglutathione (GSNO) reductase activity and could be a candidate to regulate NO-signalling functions. However, there is a lack of knowledge about the tissue distribution of this enzyme in plants. Here, we have studied the localization and developmental expression of the enzyme using immunolocalization and histochemical activity assay methods. We conclude that FALDH is differentially expressed in the organs of Arabidopsis thaliana mature plants, with higher levels in roots and leaves from the first stages of development. Spatial distribution of FALDH in these two organs includes the main cell types [epidermis (Ep) and cortex (Cx) in roots, and mesophyll in leaves] and the vascular system. Arabidopsis thaliana mutants with modified levels of FALDH (both by over- and under-expression of the FALDH-encoding gene) show a significant reduction of root length, and this phenotype correlates with an overall decrease of intracellular GSH levels and alteration of spatial distribution of GSH in the root meristem. Tansgenic roots are partially insensitive to exogenous GSH, suggesting an inability to detect reduction-oxidation (redox) changes of the GSH pool and/or maintain GSH homeostasis.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Facultat de Ciències, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: M Carme
authors.initials: MC
authors.lastname: Espunya
authors.forename: Maykelis
authors.initials: M
authors.lastname: Díaz
authors.forename: Jordi
authors.initials: J
authors.lastname: Moreno-Romero
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Martínez
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000378:metabolism*; D015153:Blotting, Western; D005978:Glutathione / Q000378:metabolism*; D006706:Homeostasis; D007150:Immunohistochemistry; D018517:Plant Roots / Q000254:growth & development*; D030821:Plants, Genetically Modified
chemical_list: D000445:Aldehyde Oxidoreductases; C087006:formaldehyde dehydrogenase, glutathione-independent; D005978:Glutathione