Exogenous Proline-Mediated Abiotic Stress Tolerance in Plants: Possible Mechanisms

  • Mohamed Zouari
  • Ameni Ben Hassena
  • Lina Trabelsi
  • Bechir Ben Rouina
  • Raphaël Decou
  • Pascal LabrousseEmail author


Plants are subjected to many stresses (salinity, drought, heavy metals, temperature, etc.) that may limit their growth. As a result, plants exhibit a variety of adaptive strategies to mitigate the adverse effects of abiotic stresses. Among those strategies, the accumulation of compatible solute such as proline is the most common defensive mechanism adopted. Indeed, proline plays a highly beneficial role as an osmolyte. In addition, proline helps to stabilize subcellular structures and acts as a metal chelator. Proline may also activate the cellular antioxidant system and scavenge the reactive oxygen species (ROS). Accordingly, application of exogenous proline was investigated on plants to induce tolerance. Therefore, under salt conditions, exogenous proline might alleviate growth inhibition and ameliorate photosynthetic activity, mineral nutrition, and water status. Furthermore, it may regulate osmotic potential and decrease the effect of toxic ions by activating the enzymatic antioxidant system. Exogenous proline applied under drought stress has successfully improved physiological performance. In these conditions, these applications increased proline accumulation in cells and therefore reduce cell osmotic potential and maintain turgor. This osmotic adjustment may help plants to improve their biomass. Finally, the beneficial role of exogenous proline was also proved in plants subjected to metal stress. This organic compound may reduce the phytotoxic effects of metals through the formation of proline-metal complexes and the stimulation of enzymatic and nonenzymatic antioxidant systems. Besides, exogenous proline may protect plants subjected to metal contamination by stabilizing membranes and thereby preventing electrolyte leakage, improving water status, photosynthetic activity, and growth rate.


Exogenous proline Abiotic stress Plant tolerance Antioxidant defense system 


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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Mohamed Zouari
    • 1
  • Ameni Ben Hassena
    • 2
  • Lina Trabelsi
    • 1
  • Bechir Ben Rouina
    • 1
  • Raphaël Decou
    • 3
  • Pascal Labrousse
    • 3
    Email author
  1. 1.Laboratory of Improvement of Olive Productivity and Fruit Trees, Olive Tree Institute of Sfax, University of SfaxSfaxTunisia
  2. 2.Laboratory of Amelioration and Protection of Olive Genetic Resources, Olive Tree Institute of Sfax, University of SfaxSfaxTunisia
  3. 3.University of LimogesLimogesFrance

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