title: The transcription factor SlAREB1 confers drought, salt stress tolerance and regulates biotic and abiotic stress-related genes in tomato.
abstract: Members of the abscisic acid-responsive element binding protein (AREB)/abscisic acid-responsive element binding factor (ABF) subfamily of basic leucine zipper (bZIP) transcription factors have been implicated in abscisic acid (ABA) and abiotic stress responses in plants. Here we describe two members identified in cultivated tomato (Solanum lycopersicum), named SlAREB1 and SlAREB2. Expression of SlAREB1 and SlAREB2 is induced by drought and salinity in both leaves and root tissues, although that of SlAREB1 was more affected. In stress assays, SlAREB1-overexpressing transgenic tomato plants showed increased tolerance to salt and water stress compared to wild-type and SlAREB1-down-regulating transgenic plants, as assessed by physiological parameters such as relative water content (RWC), chlorophyll fluorescence and damage by lipoperoxidation. In order to identify SlAREB1 target genes responsible for the enhanced tolerance, microarray and cDNA-amplified fragment length polymorphism (AFLP) analyses were performed. Genes encoding oxidative stress-related proteins, lipid transfer proteins (LTPs), transcription regulators and late embryogenesis abundant proteins were found among the up-regulated genes in SlAREB1-overexpressing lines, especially in aerial tissue. Notably, several genes encoding defence proteins associated with responses to biotic stress (e.g. pathogenesis-related proteins, protease inhibitors, and catabolic enzymes) were also up-regulated by SlAREB1 overexpression, suggesting that this bZIP transcription factor is involved in ABA signals that participate in abiotic stress and possibly in response to pathogens.
authors.affiliation: Instituto de Biología Vegetal y Biotecnología, Universidad de Talca,Talca, Chile.
authors.forename: Sandra
authors.initials: S
authors.lastname: Orellana
authors.forename: Mónica
authors.initials: M
authors.lastname: Yañez
authors.forename: Analía
authors.initials: A
authors.lastname: Espinoza
authors.forename: Isabel
authors.initials: I
authors.lastname: Verdugo
authors.forename: Enrique
authors.initials: E
authors.lastname: González
authors.forename: Simón
authors.initials: S
authors.lastname: Ruiz-Lara
authors.forename: José A
authors.initials: JA
authors.lastname: Casaretto
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D054458:Amplified Fragment Length Polymorphism Analysis; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D055864:Droughts; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress; D010940:Plant Proteins / Q000378:metabolism; D054712:Salinity; D055049:Salt Tolerance
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D010940:Plant Proteins; D000040:Abscisic Acid