NaCl-stimulated ATP synthesis in mitochondria of a halophyte Mesembryanthemum crystallinum L.

Dan Q Tran,Ayako Konishi,Masahiro Morokuma,Masanori Toyota,Sakae Agarie

doi:10.1080/1343943x.2019.1682462

Abstract

ABSTRACTSalinity adaptive responses in halophytes include energy-requiring processes, but the mechanism supplying ATP to meet the increased ATP demand remains unclear. In the present study, we examined the effects of NaCl on ATP synthesis in mitochondria isolated from a halophyte, the common ice plant (Mesembryanthemum crystallinum L.). The ATP synthesis rate was maintained or enhanced with increasing osmotic pressures ranged from 0.2 to 2.0 MPa in the assay mixtures containing NaCl, whereas it was decreased in the mixtures with the equivalent osmotic pressures generated by sorbitol only. Also, the ATP synthesis rate was enhanced with increasing NaCl concentrations ranged from 50 to 350 mM in the assay mixtures with fixed (2.0 MPa) osmotic pressure. These results suggested a mechanism of enhanced ATP synthesis in the mitochondria by the ionic effects of NaCl, which might play an important role in the adaptation of the ice plant under salinity.

Highlights

Salinity, which is caused by the presence of NaCl in soils, is one of the major abiotic stresses limiting plant growth and agricultural production (Flowers & Colmer, 2008)
In the present study, we found that the ATP synthesis in the mitochondria isolated from both the plants grown without and with NaCl was enhanced by 50–350 mM NaCl in the assay mixtures (Figures 2 and 3)
The ATP synthesis enhancement in halophytes has been suggested in some previous reports (Kumari et al, 2015; Shabala, 2013; Yeo, 1983), the present study is the first report of the direct measurement of ATP synthesis that was enhanced by NaCl

Summary

Introduction

Salinity, which is caused by the presence of NaCl in soils, is one of the major abiotic stresses limiting plant growth and agricultural production (Flowers & Colmer, 2008). Enhancement of salt tolerance in crops and application of salt-tolerant plants as alternative crops are useful solutions to maintain agricultural production (Glenn, Brown & Blumwald, 1999; Panta et al, 2014; Shabala, 2013). Halophytes are defined as salt-tolerant plants that capable of completing their life cycle under high salinity at which almost all crops die (Flowers & Colmer, 2008).

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Conclusion