title: bHLH122 is important for drought and osmotic stress resistance in Arabidopsis and in the repression of ABA catabolism.
abstract: • Although proteins in the basic helix-loop-helix (bHLH) family are universal transcription factors in eukaryotes, the biological roles of most bHLH family members are not well understood in plants. • The Arabidopsis thaliana bHLH122 transcripts were strongly induced by drought, NaCl and osmotic stresses, but not by ABA treatment. Promoter::GUS analysis showed that bHLH122 was highly expressed in vascular tissues and guard cells. Compared with wild-type (WT) plants, transgenic plants overexpressing bHLH122 displayed greater resistance to drought, NaCl and osmotic stresses. In contrast, the bhlh122 loss-of-function mutant was more sensitive to NaCl and osmotic stresses than were WT plants. • Microarray analysis indicated that bHLH122 was important for the expression of a number of abiotic stress-responsive genes. In electrophoretic mobility shift assay and chromatin immunoprecipitation assays, bHLH122 could bind directly to the G-box/E-box cis-elements in the CYP707A3 promoter, and repress its expression. Further, up-regulation of bHLH122 substantially increased cellular ABA levels. • These results suggest that bHLH122 functions as a positive regulator of drought, NaCl and osmotic signaling.
authors.affiliation: National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Liu
authors.affiliation: National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Huanhuan
authors.initials: H
authors.lastname: Tai
authors.affiliation: National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Songsong
authors.initials: S
authors.lastname: Li
authors.affiliation: National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.affiliation: Key Laboratory of Plant and Soil Interactions, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Zhao
authors.affiliation: National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Chuanxiao
authors.initials: C
authors.lastname: Xie
authors.affiliation: National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Wen-Xue
authors.initials: WX
authors.lastname: Li
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D055864:Droughts; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008353:Mannitol / Q000494:pharmacology; D009154:Mutation / Q000235:genetics; D009995:Osmosis; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
chemical_list: D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D008353:Mannitol; D012333:RNA, Messenger; D012965:Sodium Chloride; C000591864:bHLH122 protein, Arabidopsis
keywords: ABA; Arabidopsis thaliana; CYP707A3; abiotic stress; bHLH122