title: Modulation of modeled microgravity on radiation-induced bystander effects in Arabidopsis thaliana.
abstract: Both space radiation and microgravity have been demonstrated to have inevitable impact on living organisms during space flights and should be considered as important factors for estimating the potential health risk for astronauts. Therefore, the question whether radiation effects could be modulated by microgravity is an important aspect in such risk evaluation. Space particles at low dose and fluence rate, directly affect only a fraction of cells in the whole organism, which implement radiation-induced bystander effects (RIBE) in cellular response to space radiation exposure. The fact that all of the RIBE experiments are carried out in a normal gravity condition bring forward the need for evidence regarding the effect of microgravity on RIBE. In the present study, a two-dimensional rotation clinostat was adopted to demonstrate RIBE in microgravity conditions, in which the RIBE was assayed using an experimental system of root-localized irradiation of Arabidopsis thaliana (A. thaliana) plants. The results showed that the modeled microgravity inhibited significantly the RIBE-mediated up-regulation of expression of the AtRAD54 and AtRAD51 genes, generation of reactive oxygen species (ROS) and transcriptional activation of multicopy P35S:GUS, but made no difference to the induction of homologous recombination by RIBE, showing divergent responses of RIBE to the microgravity conditions. The time course of interaction between the modeled microgravity and RIBE was further investigated, and the results showed that the microgravity mainly modulated the processes of the generation or translocation of the bystander signal(s) in roots.
authors.affiliation: Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, PR China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.affiliation: Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086, PR China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, PR China.
authors.forename: Fanghua
authors.initials: F
authors.lastname: Li
authors.affiliation: Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086, PR China.
authors.forename: Huasheng
authors.initials: H
authors.lastname: Li
authors.affiliation: Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086, PR China.
authors.forename: Jinying
authors.initials: J
authors.lastname: Lu
authors.affiliation: Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, PR China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Wu
authors.affiliation: Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, PR China.
authors.forename: Yuejin
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.affiliation: Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031, PR China.
authors.forename: Po
authors.initials: P
authors.lastname: Bian
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics; D024201:Bystander Effect; D004265:DNA Helicases / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D059767:Recombinational DNA Repair; D014158:Transcription, Genetic; D014893:Weightlessness
chemical_list: D029681:Arabidopsis Proteins; C518800:RAD54 protein, Arabidopsis; D017382:Reactive Oxygen Species; D004265:DNA Helicases
keywords: DNA homologous recombination repair; Epigenetic regulation; Modeled microgravity; Radiation-induced bystander effect; Reactive oxygen species