title: The time course of long-distance signaling in radiation-induced bystander effect in vivo in Arabidopsis thaliana demonstrated using root micro-grafting.
abstract: The radiation-induced bystander effect has been demonstrated in whole organisms as well as in multicellular tissues in vitro and single-cell culture systems in vitro. However, the time course of bystander signaling, especially in whole organisms, is not clear. Long-distance bystander/abscopal effects in vivo in plants have been demonstrated by our group. Plant grafting is a useful experimental tool for studying the root-shoot signaling of plants. In the present study, we developed a root micro-grafting technique with young seedlings of Arabidopsis thaliana in which the bystander signaling communication of root-to-shoot could easily be stopped or started at specific times after root irradiation. Using this methodology, we demonstrated the time course of long-distance signaling in radiation-induced bystander effects at the level of the organism using the expression level of the AtRAD54 gene as a biological end point. Briefly, an 8-h accumulation of damage signals in bystander parts after irradiation was essential for eliciting a bystander response. The protraction of signal accumulation was not related to the transmission speed of signaling molecules in plants and did not result from the delayed initiation of bystander signals in targeted root cells. It was suggested that the bystander effect might be induced jointly by multiple bystander signals initiated at different stages after irradiation. Moreover, reactive oxygen species (ROS) were shown to be implicated in the response process of bystander cells to radiation damage signals rather than in the generation of bystander signals in targeted cells.
authors.affiliation: Key Laboratory of Ion Beam Bio-engineering, Institute of Technical Biology and Agricultural Engineering, Chinese Academy of Sciences, Shushanhu Road 350#, Hefei 230031, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Wang
authors.forename: Fanghua
authors.initials: F
authors.lastname: Li
authors.forename: Shuyan
authors.initials: S
authors.lastname: Xu
authors.forename: Po
authors.initials: P
authors.lastname: Bian
authors.forename: Yuejin
authors.initials: Y
authors.lastname: Wu
authors.forename: Lijun
authors.initials: L
authors.lastname: Wu
authors.forename: Zengliang
authors.initials: Z
authors.lastname: Yu
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000235:genetics; D024201:Bystander Effect / Q000235:genetics / Q000528:radiation effects*; D053960:DNA Breaks / Q000528:radiation effects; D004265:DNA Helicases / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D005966:Glucuronidase / Q000378:metabolism; D035261:Plant Components, Aerial / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D018517:Plant Roots / Q000166:cytology* / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D030821:Plants, Genetically Modified; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000528:radiation effects*; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins; C518800:RAD54 protein, Arabidopsis; D017382:Reactive Oxygen Species; D005966:Glucuronidase; D004265:DNA Helicases