Enhanced osmotic stress tolerance in Medicago truncatula plants overexpressing the DNA repair gene MtTdp2α (tyrosyl-DNA phosphodiesterase 2)

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• 作者：Massimo Confalonieri (1)
  Matteo Faè (2)
  Alma Balestrazzi (2)
  Mattia Donà (2)
  Anca Macovei (2) (3)
  Alberto Valassi (2)
  Giorgio Giraffa (1)
  Daniela Carbonera (2)
  
• 关键词：DNA repair ; Double strand breaks ; Medicago truncatula ; Osmotic stress ; Transgenic plant ; Tyrosyl ; DNA phosphodiesterase 2
• 刊名：Plant Cell, Tissue and Organ Culture
• 出版年：2014
• 出版时间：February 2014
• 年：2014
• 卷：116
• 期：2
• 页码：187-203
• 全文大小：709 KB
• 作者单位：Massimo Confalonieri (1)
  Matteo Faè (2)
  Alma Balestrazzi (2)
  Mattia Donà (2)
  Anca Macovei (2) (3)
  Alberto Valassi (2)
  Giorgio Giraffa (1)
  Daniela Carbonera (2)
  
  1. Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca per le Produzioni Foraggere e Lattiero-Casearie (CRA-FLC), viale Piacenza 29, 29600, Lodi, Italy
  2. Dipartimento di Biologia e Biotecnologie ‘L. Spallanzani- Università degli Studi di Pavia, Via Ferrata 9, 27100, Pavia, Italy
  3. International Rice Research Institute (IRRI), Los Banos, Philippines
  
• ISSN：1573-5044

文摘

No information is currently available in plants concerning the tyrosyl-DNA phosphodiesterase 2 (Tdp2) enzyme which in animals is involved in the removal of DNA topoisomerase II-mediated DNA damage and cell proliferation/differentiation signaling. Bioinformatic investigation revealed the occurrence in the plant kingdom of three distinct Tdp2 isoforms, named α, β and γ. The MtTdp2α gene from Medicago truncatula Gaertn., encoding a protein with putative nuclear localization signal and chloroplast transit peptide, was significantly up-regulated in response to osmotic stress induced by polyethylene glycol. The transgenic M. truncatula lines Tdp2α-13C and Tdp2α-28 overexpressing the MtTdp2α gene were characterised by enhanced tolerance to both osmotic and photo-oxidative stress. According to single cell gel electrophoresis, MtTdp2α gene overexpression prevented accumulation of double strand breaks in absence and presence of osmotic stress. Interestingly, the MtMRE11, MtRAD50 and MtNBS1 genes involved in double strand break sensing/repair were significantly up-regulated in the MtTdp2α-overexpressing plants grown under physiological conditions and no further up-regulation occurred in response the osmotic agent. The Tdp2α-13C and Tdp2α-28 lines also showed significant up-regulation of several genes essential for the control of DNA topology and genome maintenance, such as MtTdp1α, MtTop2 (DNA topoisomerase II) and MtGYR (DNA gyrase). The role of MtTdp2α gene in enhancing the plant response to genotoxic injury under osmotic stress is discussed.