title: Molecular characterization of novel TaNAC genes in wheat and overexpression of TaNAC2a confers drought tolerance in tobacco.
abstract: Plant-specific NAC (NAM/ATAF/CUC) transcription factors (TFs) have been reported to play a role in diverse stress responses and developmental processes. We show here that six new genes encoding NAC TFs in wheat (Triticum aestivum) were identified (named as TaNAC2a, TaNAC4a, TaNAC6, TaNAC7, TaNAC13 and TaNTL5, respectively), and we classified them into three groups: stress-related NACs, development-related NACs and NTLs (membrane-associated TFs belonging to NAC) by phylogenetic analysis. All TaNACs were induced by one or several kinds of stress treatments including dehydration, salinity and low temperature, whereas different genes showed different expression levels. All these TaNACs, except TaNAC7, were proven to have transcriptional activation activity in the yeast strain AH109 by transactivation analysis. Furthermore, subcellular localization analysis revealed that four TaNAC:GFP (green fluorescent protein) fusion proteins were localized in the nucleus, TaNAC2a:GFP mainly located in the nucleus and the plasma membrane, TaNTL5:GFP was associated with the membrane, while truncated TaNTL5(ΔTM):GFP (lacking the transmembrane motif) was detected exclusively in the nucleus. Semi-quantitative reverse transcription polymerase chain reaction analysis demonstrated that five genes exhibited organ-specific expression. Transgenic tobacco plants overexpressing TaNAC2a showed higher fresh weight and dry weight than non-transgenic plants under drought condition, which indicated that the transgene improved tobacco tolerance to drought treatment. Together, these results provided a preliminary characterization of six TaNACs, which possessed a potential role in improving stress tolerance and the regulation of development in wheat, and suggested that TaNAC2a was potentially useful for engineering drought tolerant plants.
authors.affiliation: Beijing Engineering and Technique Research Center of Hybrid Wheat, Beijing Academy of Agricultural and Forestry Science, Beijing 100097, People's Republic of China.
authors.forename: YiMiao
authors.initials: Y
authors.lastname: Tang
authors.forename: MeiYing
authors.initials: M
authors.lastname: Liu
authors.forename: ShiQing
authors.initials: S
authors.lastname: Gao
authors.forename: Zhao
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: ChangPing
authors.initials: C
authors.lastname: Zhao
authors.forename: FengTing
authors.initials: F
authors.lastname: Zhang
authors.forename: XuePing
authors.initials: X
authors.lastname: Chen
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D055864:Droughts; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055051:Salt-Tolerant Plants / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014170:Transformation, Genetic; D019076:Transgenes; D014908:Triticum / Q000235:genetics* / Q000502:physiology
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors; D012965:Sodium Chloride; D000040:Abscisic Acid