title: Expression of wild soybean WRKY20 in Arabidopsis enhances drought tolerance and regulates ABA signalling.
abstract: The WRKY-type transcription factors are involved in plant development and stress responses, but how the regulation of stress tolerance is related to plant development is largely unknown. GsWRKY20 was initially identified as a stress response gene using large-scale Glycine soja microarrays. Quantitative reverse transcription-PCR (qRT-PCR) showed that the expression of this gene was induced by abscisic acid (ABA), salt, cold, and drought. Overexpression of GsWRKY20 in Arabidopsis resulted in a decreased sensitivity to ABA during seed germination and early seedling growth. However, compared with the wild type, GsWRKY20 overexpression lines were more sensitive to ABA in stomatal closure, and exhibited a greater tolerance to drought stress, a decreased water loss rate, and a decreased stomatal density. Moreover, microarray and qRT-PCR assays showed that GsWRKY20 mediated ABA signalling by promoting the expression of negative regulators of ABA signalling, such as AtWRKY40, ABI1, and ABI2, while repressing the expression of the positive regulators of ABA, for example ABI5, ABI4, and ABF4. Interestingly, GsWRKY20 also positively regulates the expression of a group of wax biosynthetic genes. Further, evidence is provided to support that GsWRKY20 overexpression lines have more epicuticular wax crystals and a much thicker cuticle, which contribute to less chlorophyll leaching compared with the wild type. Taken together, the findings reveal an important role for GsWRKY20 in enhancing drought tolerance and regulating ABA signalling.
authors.affiliation: Plant Bioengineering Laboratory, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Luo
authors.forename: Xi
authors.initials: X
authors.lastname: Bai
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Sun
authors.forename: Dan
authors.initials: D
authors.lastname: Zhu
authors.forename: Baohui
authors.initials: B
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
authors.forename: Hua
authors.initials: H
authors.lastname: Cai
authors.forename: Lei
authors.initials: L
authors.lastname: Cao
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.forename: Mengran
authors.initials: M
authors.lastname: Hu
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Lili
authors.initials: L
authors.lastname: Tang
authors.forename: Yanming
authors.initials: Y
authors.lastname: Zhu
mesh_terms: D000040:Abscisic Acid / Q000502:physiology*; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D003001:Cloning, Molecular; D055864:Droughts; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D018525:Germination / Q000235:genetics / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D054046:Plant Stomata / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000235:genetics / Q000254:growth & development; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D030262:Soybean Proteins / Q000235:genetics* / Q000502:physiology; D013312:Stress, Physiological / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology
chemical_list: D030262:Soybean Proteins; D014157:Transcription Factors; D000040:Abscisic Acid
keywords: ABA; WRKY.; drought; stomata; wax; wild soybean