title: Disarrangement of actin filaments and Ca²⁺ gradient by CdCl₂ alters cell wall construction in Arabidopsis thaliana root hairs by inhibiting vesicular trafficking.
abstract: Cadmium (Cd), one of the most toxic heavy metals, inhibits many cellular and physiological processes in plants. Here, the involvement of cytoplasmic Ca²⁺ gradient and actin filaments (AFs) in vesicular trafficking, cell wall deposition and tip growth was investigated during root (hair) development of Arabidopsis thaliana in response to CdCl₂ treatment. Seed germination and root elongation were prevented in a dose- and time-dependent manner by CdCl₂ treatment. Fluorescence labelling and non-invasive detection showed that CdCl₂ inhibited extracellular Ca²⁺ influx, promoted intracellular Ca²⁺ efflux, and disturbed the cytoplasmic tip-focused Ca²⁺ gradient. In vivo labelling revealed that CdCl₂ modified actin organization, which subsequently contributed to vesicle trafficking. Transmission electron microscopy revealed that CdCl₂ induced cytoplasmic vacuolization and was detrimental to organelles such as mitochondria and endoplasmic reticulum (ER). Finally, immunofluorescent labelling and Fourier transform infrared (FTIR) analysis indicated that configuration/distribution of cell wall components such as pectins and cellulose was significantly altered in response to CdCl₂. Our results indicate that CdCl₂ induces disruption of Ca²⁺ gradient and AFs affects the distribution of cell wall components in root hairs by disturbing vesicular trafficking in A. thaliana.
authors.affiliation: Key Laboratory of Photosynthesis and Molecular Environmental Physiology, Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing 100093, China.
authors.forename: Jun-Ling
authors.initials: JL
authors.lastname: Fan
authors.forename: Xue-Zhi
authors.initials: XZ
authors.lastname: Wei
authors.forename: Li-Chuan
authors.initials: LC
authors.lastname: Wan
authors.forename: Ling-Yun
authors.initials: LY
authors.lastname: Zhang
authors.forename: Xue-Qin
authors.initials: XQ
authors.lastname: Zhao
authors.forename: Wei-Zhong
authors.initials: WZ
authors.lastname: Liu
authors.forename: Huai-Qin
authors.initials: HQ
authors.lastname: Hao
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Zhang
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects* / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D019256:Cadmium Chloride / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D005453:Fluorescence; D018613:Microscopy, Confocal; D010368:Pectins / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D036226:Seedlings / Q000187:drug effects / Q000648:ultrastructure; D012639:Seeds / Q000187:drug effects / Q000254:growth & development; D017550:Spectroscopy, Fourier Transform Infrared; D014617:Vacuoles / Q000187:drug effects
chemical_list: D015220:Calcium Channels; D010368:Pectins; D019256:Cadmium Chloride; D002118:Calcium