title: Overexpression of Arabidopsis thaliana LTL1, a salt-induced gene encoding a GDSL-motif lipase, increases salt tolerance in yeast and transgenic plants.
abstract: Genes involved in the mechanisms of plant responses to salt stress may be used as biotechnological tools for the genetic improvement of salt tolerance in crop plants. This would help alleviate the increasing problem of salinization of lands cultivated under irrigation in arid and semi-arid regions. We have isolated a novel halotolerance gene from Arabidopsis thaliana, A. thaliana Li-tolerant lipase 1 (AtLTL1), on the basis of the phenotype of tolerance to LiCl conferred by its expression in yeast. AtLTL1 encodes a putative lipase of the GDSL-motif family, which includes bacterial and a very large number of plant proteins. In Arabidopsis, AtLTL1 expression is rapidly induced by LiCl or NaCl, but not by other abiotic stresses. Overexpression of AtLTL1 increases salt tolerance in transgenic Arabidopsis plants, compared to non-transformed controls, allowing germination of seeds in the presence of toxic concentrations of LiCl and NaCl, and stimulating vegetative growth, flowering and seed set in the presence of NaCl. These results clearly point to a role of AtLTL1 in the mechanisms of salt tolerance. In addition, we show that AtLTL1 expression is also activated, although only transiently, by salicylic acid (SA), suggesting that the lipase could also be involved in defence reactions against pathogens.
authors.affiliation: Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Naranjo
authors.forename: Javier
authors.initials: J
authors.lastname: Forment
authors.forename: Marta
authors.initials: M
authors.lastname: Roldán
authors.forename: Ramón
authors.initials: R
authors.lastname: Serrano
authors.forename: Oscar
authors.initials: O
authors.lastname: Vicente
mesh_terms: D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics*; D001483:Base Sequence; D018076:DNA, Complementary; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant; D008049:Lipase / Q000737:chemistry / Q000235:genetics*; D018021:Lithium Chloride / Q000494:pharmacology*; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D008049:Lipase; D018021:Lithium Chloride