title: Extracellular ATP signaling is mediated by H₂O₂ and cytosolic Ca²⁺ in the salt response of Populus euphratica cells.
abstract: Extracellular ATP (eATP) has been implicated in mediating plant growth and antioxidant defense; however, it is largely unknown whether eATP might mediate salinity tolerance. We used confocal microscopy, a non-invasive vibrating ion-selective microelectrode, and quantitative real time PCR analysis to evaluate the physiological significance of eATP in the salt resistance of cell cultures derived from a salt-tolerant woody species, Populus euphratica. Application of NaCl (200 mM) shock induced a transient elevation in [eATP]. We investigated the effects of eATP by blocking P2 receptors with suramin and PPADS and applying an ATP trap system of hexokinase-glucose. We found that eATP regulated a wide range of cellular processes required for salt adaptation, including vacuolar Na⁺ compartmentation, Na⁺/H⁺ exchange across the plasma membrane (PM), K⁺ homeostasis, reactive oxygen species regulation, and salt-responsive expression of genes related to Na⁺/H⁺ homeostasis and PM repair. Furthermore, we found that the eATP signaling was mediated by H₂O₂ and cytosolic Ca²⁺ released in response to high salt in P. euphratica cells. We concluded that salt-induced eATP was sensed by purinoceptors in the PM, and this led to the induction of downstream signals, like H₂O₂ and cytosolic Ca²⁺, which are required for the up-regulation of genes linked to Na⁺/H⁺ homeostasis and PM repair. Consequently, the viability of P. euphratica cells was maintained during a prolonged period of salt stress.
authors.affiliation: College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Sun
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhang
authors.forename: Shurong
authors.initials: S
authors.lastname: Deng
authors.forename: Chunlan
authors.initials: C
authors.lastname: Zhang
authors.forename: Meijuan
authors.initials: M
authors.lastname: Wang
authors.forename: Mingquan
authors.initials: M
authors.lastname: Ding
authors.forename: Rui
authors.initials: R
authors.lastname: Zhao
authors.forename: Xin
authors.initials: X
authors.lastname: Shen
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Zhou
authors.forename: Cunfu
authors.initials: C
authors.lastname: Lu
authors.forename: Shaoliang
authors.initials: S
authors.lastname: Chen
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D059828:Plant Cells / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D032107:Populus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D055049:Salt Tolerance / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D012965:Sodium Chloride; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; D002118:Calcium