Changes to Intracellular Ca2+ and Its Sensors Triggered by NaCl Stress in Pears


The responses of Ca2+ signaling mechanism to salt stress in pears are poorly understood. In this study, we investigated the difference in the Ca2+ signal responses to NaCl stress in two pear species (Pyrus betulaefolia Bunge. and P. bretschneideri Rehd. cv. ‘Xuehua’). Pear protoplasts were treated with 100 mM NaCl alone and NaCl combined with various chemical agents before changes in intracellular Ca2+ levels and the expression of Ca2+ sensor-related genes were analyzed. NaCl stress caused elevated Ca2+ levels in protoplasts labeled with the calcium indicator Fluo-3/AM. The Ca2+ signal increased earlier in P. betulaefolia than in the ‘Xuehua’ cultivar. The cytoplasmic Ca2+ bursts induced by NaCl stress were significantly constrained by the chemical agents supplied to both species. The plasma-membrane Ca2+ channel inhibitor LaCl3 and extracellular Ca2+ chelator EGTA had greater inhibitory effects than the intracellular Ca2+ chelator BAPTA/AM. Under NaCl stress, upregulation of PbCBL10 and genes in the classes PbCDPK and PbCIPK occurred more quickly in P. betulaefolia than the ‘Xuehua’ cultivar. In conclusion, NaCl stress stimulates Ca2+ signaling in pear cells, the ions for which are taken from extracellular and intracellular Ca2+ stores. Furthermore, the accumulation of cytoplasmic Ca2+ mediates early expression of Ca2+ sensor-related genes, especially PbCDPK1. Thus the response of Ca2+ signal plays pivotal roles, which enhance the salt tolerance of pear.

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This work was supported by the Key Project of the Key Research and Development Program of Shanxi Province, China (project nos. 201703D 221015-2 and 201703D211001).

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Correspondence to J. Li or L. Li.

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The authors declare that they have no conflict of interest. This article does not contain any studies involving animals or human participants as objects of research.

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Abbreviations: 6-BA—6-benzylaminopurine; CaM—calmodulin, CBL—calcineurin B-like protein; CDPK—calcium-dependent protein kinase; CIPK—CBL-interacting protein kinase; CPW—cell protoplast wash; FDA—fluorescein diacetate; IBA—indole-3-butytric acid; LaCl3—lanthanum chloride; SOS—salt-overly-sensitive.

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Li, J., Xie, B., Liu, Y. et al. Changes to Intracellular Ca2+ and Its Sensors Triggered by NaCl Stress in Pears. Russ J Plant Physiol 67, 1144–1151 (2020).

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  • Pyrus betulaefolia
  • Pyrus bretschneideri
  • NaCl stress
  • cytoplasmic Ca2+
  • Ca2+ sensor -related genes