title: Copper regulates primary root elongation through PIN1-mediated auxin redistribution.
abstract: The heavy metal copper (Cu) is an essential microelement required for normal plant growth and development, but it inhibits primary root growth when in excess. The mechanism underlying how excess Cu functions in this process remains to be further elucidated. Here, we report that a higher concentration of CuSO4 inhibited primary root elongation of Arabidopsis seedlings by affecting both the elongation and meristem zones. In the meristem zone, meristematic cell division potential was reduced by excess Cu. Further experiments showed that Cu can modulate auxin distribution, resulting in higher auxin activities in both the elongation and meristem zones of Cu-treated roots based on DR5::GUS expression patterns. This Cu-mediated auxin redistribution was shown to be responsible for Cu-mediated inhibition of primary root elongation. Additional genetic and physiological data demonstrated that it was PINFORMED1 (PIN1), but not PIN2 or AUXIN1 (AUX1), that regulated this process. However, Cu-induced hydrogen peroxide accumulation did not contribute to Cu-induced auxin redistribution for inhibition of root elongation. When the possible role of ethylene in this process was analyzed, Cu had a similar impact on the root elongation of both the wild type and the ein2-1 mutant, implying that Cu-mediated inhibition of primary root elongation was not due to the ethylene signaling pathway.
authors: College of Life Sciences, Wuhan University, Wuhan 430072, China.
authors: Hong-Mei
authors: HM
authors: Yuan
authors: Heng-Hao
authors: HH
authors: Xu
authors: Wen-Cheng
authors: WC
authors: Liu
authors: Ying-Tang
authors: YT
authors: Lu
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D003300:Copper / Q000494:pharmacology*; D019327:Copper Sulfate / Q000494:pharmacology; D005030:Ethylenes / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D018519:Meristem / Q000187:drug effects / Q000254:growth & development; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D011193:Potassium Iodide / Q000494:pharmacology; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D029681:Arabidopsis Proteins; D003300:Copper; D019327:Copper Sulfate; D005030:Ethylenes; D006861:Hydrogen Peroxide; D007210:Indoleacetic Acids; D026901:Membrane Transport Proteins; D011193:Potassium Iodide; C100794:AUX1 protein, Arabidopsis; C116363:PIN1 protein, Arabidopsis; C117013:AT5G57090 protein, Arabidopsis; C036216:ethylene
keywords: Arabidopsis thaliana; Auxin; Cu toxicity; Ethylene; ROS; Root elongation