title: Improvement and transcriptome analysis of root architecture by overexpression of Fraxinus pennsylvanica DREB2A transcription factor in Robinia pseudoacacia L. 'Idaho'.
abstract: Transcription factors play a key role to enable plants to cope with abiotic stresses. DREB2 regulates the expression of several stress-inducible genes and constitutes major hubs in the water stress signalling webs. We cloned and characterized a novel gene encoding the FpDREB2A transcription factor from Fraxinus pennsylvanica, and a yeast activity assay confirmed its DRE binding and transcription activation. Overexpression of FpDREB2A in R. pseudoacacia showed enhanced resistance to drought stress. The transgenic plant survival rate was significantly higher than that of WT in soil drying and re-watering treatments. Transgenic lines showed a dramatic change in root architecture, and horizontal and vertical roots were found in transgenic plants compared to WT. The vertical roots penetrated in the field soil to more than 60 cm deep, while horizontal roots expanded within the top 20-30 cm of the soil. A physiological test demonstrated that chlorophyll contents were more gradually reduced and that soluble sugars and proline levels elevated more sharply but malondialdehyde level stayed the same (P < 0.05). Plant hormone levels of abscisic acid and IAA were higher than that of WT, while gibberellins and zeatin riboside were found to be lower. The root transcriptomes were sequenced and annotated into 2011 differential expression genes (DEGs). The DEGs were categorized in 149 pathways and were found to be involved in plant hormone signalling, transcription factors, stimulus responses, phenylalanine, carbohydrate and other metabolic pathways. The modified pathways in plant hormone signalling are thought to be the main cause of greater horizontal and vertical root development, in particular.
authors.affiliation: College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiu
authors.affiliation: College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China.
authors.forename: Arshad
authors.initials: A
authors.lastname: Iqbal
authors.affiliation: College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhu
authors.affiliation: College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China.
authors.forename: Guodong
authors.initials: G
authors.lastname: Wu
authors.affiliation: College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Chang
authors.affiliation: College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Yanqing No. 1 Vocational School, Beijing, China.
authors.forename: Wenbiao
authors.initials: W
authors.lastname: Zhang
authors.affiliation: College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China.
authors.forename: Huiming
authors.initials: H
authors.lastname: Zeng
authors.affiliation: Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Shouyi
authors.initials: S
authors.lastname: Chen
authors.affiliation: College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing, China.
authors.forename: Huafang
authors.initials: H
authors.lastname: Wang
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D031661:Fraxinus / Q000235:genetics*; D008315:Malondialdehyde / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D031301:Robinia / Q000033:anatomy & histology / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D059467:Transcriptome
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors; D002734:Chlorophyll; D008315:Malondialdehyde; D011392:Proline
keywords: DREB2A; Robinia pseudoacacia; root architecture; transcriptome analysis; vertical root; yeast one-hybrid