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.

Coping with Stresses: Roles of Calcium- and Calcium/Calmodulin-Regulated Gene Expression

“…The types of genes that AREB/ABF factors upregulate under water stress include regulatory proteins (phosphatases, kinases, and TFs) and functional genes encoding late embryogenesis abundant (LEA) proteins (Yoshida et al, 2010). In tomato, the drought-and salinity-induced SlAREB1 and SlAREB2 confer tolerance to water stress by activating genes encoding oxidative stress-related proteins, lipid transfer proteins, transcription regulators, and LEA proteins (Orellana et al, 2010).…”

Interaction of aluminium and drought stress on root growth and crop yield on acid soils

“…The transcription factors bZIP and MYB are responsible for the down-stream regulation of ABA-dependent genes Yamaguchi-Shinozaki 1997, 2007). The consistency of the expression of bZIP, MYB, and ABA-dependent genes such as SUS (sucrose synthase), PvLEA18 (late embryogenesis abundant protein), KS-DHN(KS-type dehydrin) and LTP (lipid-transfer protein) (Brocard-Gifford et al 2004;Hundertmark and Hincha 2008;Orellana et al 2010) with the change of ABA accumulation and the expression of NCED in the root tips of common bean under Al and drought stress, suggest that the Al toxicity-enhanced drought sensitivity of the root apex is due to the impact of the gene regulatory network involved in ABA signal transduction ). In addition to ABA, ethylene is implicated in the inhibition of root elongation (Le et al 2001).…”

Expression profiling of PAP3, BZIP, and P5CS genes in soybean underdrought stress conditions

“…The BZIP gene is a transcription factor in signal transduction during abiotic stresses and its expression has been reported in soybean (Gao et al, 2011), maize, and transformed Arabidopsis by ZmBZIP72 in response to drought, salinity, chilling, ABA, and pathogens (Ying et al, 2012), and in Arabidopsis thaliana and rice in response to heat and hydrogen peroxide (Tang et al, 2012). The intracellular determination of GmBZIP showed that it is a nuclear-encoded defense protein in relation to abiotic responses in tomato (Orellana et al, 2010). In this research, the increase in GmBZIP gene expression in soybean leaf and root tissues under drought stress was 76% and 70%, respectively, in compared to the same tissues in the nonstressed plants.…”