title: bHLH106 Integrates Functions of Multiple Genes through Their G-Box to Confer Salt Tolerance on Arabidopsis.
abstract: An activation-tagging methodology was applied to dedifferentiated calli of Arabidopsis to identify new genes involved in salt tolerance. This identified salt tolerant callus 8 (stc8) as a gene encoding the basic helix-loop-helix transcription factor bHLH106. bHLH106-knockout (KO) lines were more sensitive to NaCl, KCl, LiCl, ABA, and low temperatures than the wild-type. Back-transformation of the KO line rescued its phenotype, and over-expression (OX) of bHLH106 in differentiated plants exhibited tolerance to NaCl. Green fluorescent protein (GFP) fused with bHLH106 revealed that it was localized to the nucleus. Prepared bHLH106 protein was subjected to electrophoresis mobility shift assays against E-box sequences (5'-CANNTG-3'). The G-box sequence 5'-CACGTG-3' had the strongest interaction with bHLH106. bHLH106-OX lines were transcriptomically analyzed, and resultant up- and down-regulated genes selected on the criterion of presence of a G-box sequence. There were 198 genes positively regulated by bHLH106 and 36 genes negatively regulated; these genes possessed one or more G-box sequences in their promoter regions. Many of these genes are known to be involved in abiotic stress response. It is concluded that bHLH106 locates at a branching point in the abiotic stress response network by interacting directly to the G-box in genes conferring salt tolerance on plants.
authors.affiliation: Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1-52 Yada, Suruga, Shizuoka 422-8526, Japan.
authors.forename: Aftab
authors.initials: A
authors.lastname: Ahmad
authors.affiliation: Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1-52 Yada, Suruga, Shizuoka 422-8526, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Niwa
authors.affiliation: Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1-52 Yada, Suruga, Shizuoka 422-8526, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Goto
authors.affiliation: Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1-52 Yada, Suruga, Shizuoka 422-8526, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ogawa
authors.affiliation: Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1-52 Yada, Suruga, Shizuoka 422-8526, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Shimizu
authors.affiliation: Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1-52 Yada, Suruga, Shizuoka 422-8526, Japan.
authors.forename: Akane
authors.initials: A
authors.lastname: Suzuki
authors.affiliation: Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1-52 Yada, Suruga, Shizuoka 422-8526, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Laboratory of Plant Molecular Improvement, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 1-52 Yada, Suruga, Shizuoka 422-8526, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Kobayashi
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000502:physiology; D051790:G-Box Binding Factors / Q000235:genetics* / Q000502:physiology; D055786:Gene Knockout Techniques; D017343:Genes, Plant / Q000235:genetics / Q000502:physiology*; D019077:Helix-Turn-Helix Motifs / Q000235:genetics* / Q000502:physiology; D030821:Plants, Genetically Modified; D060888:Real-Time Polymerase Chain Reaction; D055049:Salt Tolerance / Q000235:genetics* / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D051790:G-Box Binding Factors; C000607106:bHLH106 protein, Arabidopsis