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NaCl- and cold-induced stress activate different Ca2+-permeable channels in Arabidopsis thaliana

Wang, Chao, Teng, Yibo, Zhu, Shan, Zhang, Linlin, Liu, Xunyan
Plant growth regulation 2019 v.87 no.2 pp. 217-225
Arabidopsis thaliana, additive effect, aequorin, agricultural productivity, calcium, calcium channels, cold, cold stress, plant growth, plasma membrane, salinity, signal transduction, sodium chloride, temperature
Salinity (NaCl) and low temperatures significantly affect plant growth, development, and agricultural productivity. Both these stresses trigger an increase in free cytosolic Ca²⁺ concentration ([Ca²⁺]ᵢ) via Ca²⁺ influx across the plasma membrane. However, the interaction between salinity- and low temperature-induced [Ca²⁺]ᵢ increases are still poorly understood. We used aequorin to investigate the NaCl- and cold-induced [Ca²⁺]ᵢ signals in Arabidopsis thaliana. We found that the combination of NaCl and cold stimuli induced a greater increase in [Ca²⁺]ᵢ than that by either NaCl or cold separately. Therefore, we showed that these factors had an additive effect on [Ca²⁺]ᵢ increase. Following a pre-treatment of either NaCl or cold, the increase in [Ca²⁺]ᵢ significantly declined in response to a second NaCl treatment or cold exposure. After pre-treatment with NaCl, a subsequent cold stimulus suppressed [Ca²⁺]ᵢ increase to a lesser degree than that by a second NaCl treatment. A similar response was observed after pre-treatment with cold and subsequent treatment with NaCl, but the peak [Ca²⁺]ᵢ differed between them. We propose that NaCl-induced Ca²⁺ channels differ from those induced by cold and that a feedback mechanism may exist between NaCl- and cold-evoked [Ca²⁺]ᵢ. The Ca²⁺-permeable channels activated by NaCl were similar to those induced by cold stress; however, they may be expressed in different cells and activated by different signaling pathways. Our results indicated that there is a cross-adaptation in [Ca²⁺]ᵢ changes in response to NaCl- and cold-induced stresses.