Calcium supplementation improves in vitro salt tolerance of date palm (Phoenix dactylifera L.)

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Suliman Al-Khateeb
AA Al-Khateeb
AS Mohmand


Salt stress, date palm, Calcium, NaCl, NHX1, HA1, RT-PCR


Calcium (Ca2+) plays a major role to regulate various physiological and cellular processes. Ca2+ supplementation may activate many downstream responses in plants to regulate their growth, water status, nutrient uptake, cellular metabolism and nutritional balance under saline conditions. In vitro experiments were conducted for investigating the ameliorating effects of calcium under saline conditions in date palm (Phoenix dactylifera L) cultivar, Khalas. The plantlets were subjected to NaCl stress (0, 100 and 200mM) in combination with CaCl2 (0, 5 and 10mM). Ionic concentrations of Ca2+, Mg2+, Na+ and K+ and K+/Na+, Ca2+/Na+, K+/Ca2+ ratios were calculated. Moreover, the growth characteristics (leaf and root number, leaf and root length, leaf and root fresh weight, leaf and root dry weight, and dry weight root/shoot ratios) were also investigated. The number of leaves were improved with the addition of Ca2+, significantly. Similarly, the 10mM Ca2+ significantly enhanced the leaf dry weight. With increasing NaCl levels, the dry weight was affected significantly with the decreasing ionic ratios. However, the supplementation of CaCl2 considerably improved these ionic ratios. With an increase in salinity, the concentrations of Na+, K+, Ca2+ and Mg2+ increased significantly. While K+/Na+ ratios decreased with increasing salt levels. However, the addition of Ca2+ significantly improved K+/Na+ ratios. The transcript expression of NHX1 and HA1 genes was also investigated. The expression of NHX1 and HA1 was increased with increasing NaCl however, the addition of CaCl2 remarkably reduced the expression of both genes. The expression of NHX1 was more prominent in roots than shoots.


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[1] Safdar H, Amin A, Shafiq Y, Ali A, Yasin R, Shoukat A, Hussan MU, Sarwar MI: A review: impact of salinity on plant growth. Nat Sci 2019, 17:34-40.
[2] Ruan SL, Ma HS, Wang SH, Fu YP, Xin Y, Liu WZ, Wang F, Tong JX, Wang SZ, Chen HZ: Proteomic identification of OsCYP2, a rice cyclophilin that confers salt tolerance in rice (Oryza sativa L.) seedlings when overexpressed. Bmc Plant Biol 2011, 11.
[3] Munns R, Gilliham M: Salinity tolerance of crops - what is the cost? New Phytol 2015, 208:668-73.
[4] Flowers TJ, Colmer TD: Plant salt tolerance: adaptations in halophytes. Ann Bot-London 2015, 115:327-31.
[5] Larbi A, Kchaou H, Gaaliche B, Gargouri K, Boulal H, Morales F: Supplementary potassium and calcium improves salt tolerance in olive plants. Sci Hortic-Amsterdam 2020, 260.
[6] Shabala S: Learning from halophytes: physiological basis and strategies to improve abiotic stress tolerance in crops. Ann Bot-London 2013, 112:1209-21.
[7] Deinlein U, Stephan AB, Horie T, Luo W, Xu GH, Schroeder JI: Plant salt-tolerance mechanisms. Trends Plant Sci 2014, 19:371-9.
[8] de Freitas PAF, de Carvalho HH, Costa JH, Miranda RD, Saraiva KDD, de Oliveira FDB, Coelho DG, Prisco JT, Gomes E: Salt acclimation in sorghum plants by exogenous proline: physiological and biochemical changes and regulation of proline metabolism. Plant Cell Rep 2019, 38:403-16.
[9] Yang YQ, Wu YJ, Ma L, Yang ZJ, Dong QY, Li QP, Ni XP, Kudla J, Song CP, Guo Y: The Ca2+ Sensor SCaBP3/CBL7 Modulates Plasma Membrane H+-ATPase Activity and Promotes Alkali Tolerance in Arabidopsis. Plant Cell 2019, 31:1367-84.
[10] Wang LM, Bu XL, Chen JL, Huang DF, Luo T: Effects of Nacl on Plant Growth, Root Ultrastructure, Water Content, and Ion Accumulation in a Halophytic Seashore Beach Plum (Prunus Maritima). Pak J Bot 2018, 50:863-9.
[11] Morgan SH, Maity PJ, Geilfus CM, Lindberg S, Muehling KH: Leaf ion homeostasis and plasma membrane H+-ATPase activity in Vicia faba change after extra calcium and potassium supply under salinity. Plant Physiol Bioch 2014, 82:244-53.
[12] Souguir M, Araújo MEM, Chérif H, Tarchoun N: Supplemental calcium nitrate mitigates NaCl-induced biochemical, physiological, and antioxidant changes in sesame. International Journal of Vegetable Science 2019, 25:3-26.
[13] Tanveer K, Gilani S, Hussain Z, Ishaq R, Adeel M, Ilyas N: Effect of salt stress on tomato plant and the role of calcium. J Plant Nutr 2020, 43:28-35.
[14] Roy PR, Tahjib-Ul-Arif M, Polash MAS, Hossen MZ, Hossain MA: Physiological mechanisms of exogenous calcium on alleviating salinity-induced stress in rice (Oryza sativa L.). Physiol Mol Biol Pla 2019, 25:611-24.
[15] Agarwal PK, Shukla PS, Gupta K, Jha B: Bioengineering for Salinity Tolerance in Plants: State of the Art. Mol Biotechnol 2013, 54:102-23.
[16] Shao HB, Chu LY, Lu ZH, Kang CM: Primary antioxidant free radical scavenging and redox signaling pathways in higher plant cells. Int J Biol Sci 2008, 4:8-14.
[17] Agarwal PK, Jha B: Transcription factors in plants and ABA dependent and independent abiotic stress signalling. Biol Plantarum 2010, 54:201-12.
[18] Isayenkov SV: Genetic sources for the development of salt tolerance in crops. Plant Growth Regul 2019, 89:1-17.
[19] Moshaei MR, Nematzadeh GA, Askari H, Nejad ASM, Pakdin A: Quantitative gene expression analysis of some sodium ion transporters under salinity stress in Aeluropus littoralis. Saudi J Biol Sci 2014, 21:394-9.
[20] Fan YF, Wan SM, Jiang YS, Xia YQ, Chen XH, Gao MZ, Cao YX, Luo YH, Zhou Y, Jiang XY: Over-expression of a plasma membrane H+-ATPase SpAHA1 conferred salt tolerance to transgenic Arabidopsis. Protoplasma 2018, 255:1827-37.
[21] El Mahi H, Perez-Hormaeche J, De Luca A, Villalta I, Espartero J, Gamez-Arjona F, Fernandez JL, Bundo M, Mendoza I, Mieulet D, Lalanne E, Lee SY, Yun DJ, Guiderdoni E, Aguilar M, Leidi EO, Pardo JM, Quintero FJ: A Critical Role of Sodium Flux via the Plasma Membrane Na+/H+ Exchanger SOS1 in the Salt Tolerance of Rice. Plant Physiol 2019, 180:1046-65.
[22] Tiwari V, Patel MK, Chaturvedi AK, Mishra A, Jha B: Cloning and functional characterization of the Na+/H+ antiporter (NHX1) gene promoter from an extreme halophyte Salicornia brachiata. Gene 2019, 683:233-42.
[23] Toranj S, Aliabad KK, Abbaspour H, Saeedpour A: Effect of salt stress on the genes expression of the vacuolar H+ -pyrophosphatase and Na+/H+ antiporter in Rubia tinctorum. Mol Biol Rep 2020, 47:235-45.
[24] Nguyen NT, Vu HT, Nguyen TT, Nguyen LAT, Nguyen MCD, Hoang KL, Nguyen KT, Quach TN: Co-expression of Arabidopsis AtAVP1 and AtNHX1 to Improve Salt Tolerance in Soybean. Crop Sci 2019, 59:1133-43.
[25] Yaish MW, Kumar PP: Salt tolerance research in date palm tree (Phoenix dactylifera L.), past, present, and future perspectives. Front Plant Sci 2015, 6.
[26] Al-Khateeb SA, Al-Khateeb AA, Sattar MN, Mohmand AS, El-Beltagi HS: Assessment of Somaclonal Variation in Salt-Adapted and Non-Adapted Regenerated Date Palm (Phoenix Dactylifera L.). Fresen Environ Bull 2019, 28:3686-95.
[27] Patankar HV, Al-Harrasi I, Al Kharusi L, Jana GA, Al-Yahyai R, Sunkar R, Yaish MW: Overexpression of a Metallothionein 2A Gene from Date Palm Confers Abiotic Stress Tolerance to Yeast and Arabidopsis thaliana. Int J Mol Sci 2019, 20.
[28] Al-Khateeb A, Al-Khateeb S: Effect of different combinations of growth hormones and its interaction on callogenesis. Res J Biotechnol 2015, 10:83-8.
[29] Murashige T, Skoog F: A Revised Medium for Rapid Growth and Bio Assays with Tobacco Tissue Cultures. Physiol Plantarum 1962, 15:473-97.
[30] Gomez KA, Gomez AA: Statistical procedures for agricultural research: John Wiley & Sons, 1984.
[31] SAS: SAS/STAT 12.1 User's Guide: Survey Data Analysis (book Excerpt): SAS Institute Incorporated, 2012.
[32] Ashraf MY, Tariq S, Saleem M, Khan MA, Ul Hassan SW, Sadef Y: Calcium and zinc mediated growth and physio-biochemical changes in mungbean grown under saline conditions. J Plant Nutr 2019.
[33] Liu TZ, Zhuang LL, Huang BR: Metabolic adjustment and gene expression for root sodium transport and calcium signaling contribute to salt tolerance in Agrostis grass species. Plant Soil 2019, 443:219-32.
[34] Arshi A, Ahmad A, Aref IM, Iqbal M: Calcium interaction with salinity-induced effects on growth and metabolism of soybean (Glycine max L.) cultivars. J Environ Biol 2010, 31:795-801.
[35] Han F, Sun MJ, He W, Cui XM, Pan H, Wang H, Song FP, Lou YH, Zhuge YP: Ameliorating effects of exogenous Ca2+ on foxtail millet seedlings under salt stress. Funct Plant Biol 2019, 46:407-16.
[36] Ahmad P, Abd Allah EF, Alyemeni MN, Wijaya L, Alam P, Bhardwaj R, Siddique KHM: Exogenous application of calcium to 24-epibrassinosteroid pre-treated tomato seedlings mitigates NaCl toxicity by modifying ascorbate-glutathione cycle and secondary metabolites. Sci Rep-Uk 2018, 8.
[37] Barhomi Z, Djebali W, Smaoui A, Chaibi W, Abdelly C: Contribution of NaCl excretion to salt resistance of Aeluropus littoralis (Willd) Parl. J Plant Physiol 2007, 164:842-50.
[38] Assaha DVM, Ueda A, Saneoka H, Al-Yahyai R, Yaish MW: The Role of Na+ and K+ Transporters in Salt Stress Adaptation in Glycophytes. Front Physiol 2017, 8.
[39] Nikalje GC, Variyar PS, Joshi MV, Nikam TD, Suprasanna P: Temporal and spatial changes in ion homeostasis, antioxidant defense and accumulation of flavonoids and glycolipid in a halophyte Sesuvium portulacastrum (L.) L. Plos One 2018, 13.
[40] Chen JA, Xiao QA, Wu FH, Dong XJ, He JX, Pei ZM, Zheng HL: Nitric oxide enhances salt secretion and Na+ sequestration in a mangrove plant, Avicennia marina, through increasing the expression of H+-ATPase and Na+/H+ antiporter under high salinity. Tree Physiol 2010, 30:1570-85.
[41] Yokoi S, Quintero FJ, Cubero B, Ruiz MT, Bressan RA, Hasegawa PM, Pardo JM: Differential expression and function of Arabidopsis thaliana NHX Na+/H+ antiporters in the salt stress response. Plant J 2002, 30:529-39.
[42] Fukuda A, Nakamura A, Hara N, Toki S, Tanaka Y: Molecular and functional analyses of rice NHX-type Na+/H+ antiporter genes. Planta 2011, 233:175-88.
[43] Jaarsma R, de Boer AH: Salinity Tolerance of Two Potato Cultivars (Solanum tuberosum) Correlates With Differences in Vacuolar Transport Activity. Front Plant Sci 2018, 9.
[44] Chen YY, Lu PZ, Sun P, Wei L, Chen GL, Wu D: Interactive salt-Alkali stress and exogenous Ca2+ effects on growth and osmotic adjustment of Lolium multiflorum in a coastal estuary. Flora 2017, 229:92-9.