title: A novel bHLH transcription factor PebHLH35 from Populus euphratica confers drought tolerance through regulating stomatal development, photosynthesis and growth in Arabidopsis.
abstract: Plant basic helix-loop-helix (bHLH) transcription factors (TFs) are involved in a variety of physiological processes including the regulation of plant responses to various abiotic stresses. However, few drought-responsive bHLH family members in Populus have been reported. In this study, a novel bHLH gene (PebHLH35) was cloned from Populus euphratica. Expression analysis in P. euphratica revealed that PebHLH35 was induced by drought and abscisic acid. Subcellular localization studies using a PebHLH35-GFP fusion showed that the protein was localized to the nucleus. Ectopic overexpression of PebHLH35 in Arabidopsis resulted in a longer primary root, more leaves, and a greater leaf area under well-watered conditions compared with vector control plants. Notably, PebHLH35 overexpression lines showed enhanced tolerance to water-deficit stress. This finding was supported by anatomical and physiological analyses, which revealed a reduced stomatal density, stomatal aperture, transpiration rate, and water loss, and a higher chlorophyll content and photosynthetic rate. Our results suggest that PebHLH35 functions as a positive regulator of drought stress responses by regulating stomatal density, stomatal aperture, photosynthesis and growth.
authors.affiliation: College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China; Liaoning Forestry Vocational-Technical College, Shenyang 110101, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Dong
authors.affiliation: College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China.
authors.forename: Congpeng
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Han
authors.affiliation: College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Tang
authors.affiliation: College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Liu
authors.affiliation: College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China. Electronic address: xiaxl@bjfu.edu.cn.
authors.forename: Xinli
authors.initials: X
authors.lastname: Xia
authors.affiliation: College of Biological Sciences and Technology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China. Electronic address: yinwl@bjfu.edu.cn.
authors.forename: Weilun
authors.initials: W
authors.lastname: Yin
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D051792:Basic Helix-Loop-Helix Proteins / Q000145:classification / Q000502:physiology*; D055864:Droughts; D024861:Genetic Enhancement / Q000379:methods; D018869:Heat-Shock Response / Q000502:physiology*; D010788:Photosynthesis / Q000502:physiology*; D054046:Plant Stomata / Q000235:genetics / Q000254:growth & development*; D030821:Plants, Genetically Modified / Q000502:physiology; D032107:Populus / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D014157:Transcription Factors
keywords: Drought; Populus euphratica; Stomata; Transcription factor; bHLH