Dunaliella salina exopolysaccharides: a promising biostimulant for salt stress tolerance in tomato (Solanum lycopersicum)

• Published in: Journal of applied phycology Vol. 30; no. 5; pp. 2929 - 2941
• Main Authors: EL Arroussi, H., Benhima, R., Elbaouchi, A., Sijilmassi, B., EL Mernissi, N., Aafsar, A., Meftah-Kadmiri, I., Bendaou, N., Smouni, A.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2018; Springer Nature B.V
• Subjects: 6th Congress of the International Society for Applied Phycology; Abiotic stress; Agricultural management; Antioxidants; biochemical pathways; Biomedical and Life Sciences; Biostimulants; biotic stress; Carbohydrates; catalase; crops; Dunaliella; Dunaliella salina; Ecology; Environmental conditions; environmental factors; Environmental protection; Enzymes; Exopolysaccharides; Freshwater & Marine Ecology; gas chromatography-mass spectrometry; Jasmonic acid; Life Sciences; Metabolic pathways; Metabolomics; Microalgae; moieties; osmotolerance; peroxidase; Phenolic compounds; Phenols; Plant growth; Plant Physiology; Plant Sciences; Plants (botany); potassium; Proline; protein content; root systems; roots; salinity; Salinity tolerance; salt stress; salt tolerance; Salts; shoots; sodium; Sodium chloride; Solanum lycopersicum; stress tolerance; Stresses; Superoxide dismutase; Tomatoes; uronic acids; Biostimulant; Microalgae; Salt stress; Chlorophyta; Tomato; Exopolysaccharides
• DOI: 10.1007/s10811-017-1382-1
• ISSN: 0921-8971

Microalgal exopolysaccharides represent a potential sustainable alternative for the enhancement and protection of agricultural crops including management of both biotic and abiotic stress. In the present study, we investigated the potential of Dunaliella salina exopolysaccharides (PS) to attenuate the effect of salt stress on growth of Solanum lycopersicum , which was grown under different salinity levels (3 and 6 g L −1 NaCl). The effects of PS treatment on plant growth, osmoprotectant molecules, protein content, and antioxidant enzymes activities of tomato plants under salt stress were analyzed. A metabolomics study showed that the exopolysaccharides released by D. salina contained sulfated moiety along with carbohydrates and uronic acids. The application of sulfated exopolysaccharides on tomato plants alleviated the salt stress and mitigated the decrease in length and dry weight of the plant’s shoot and root systems, as well as that of potassium (K + ), and K + /Na + ratio. Furthermore, the increase in proline, phenolic compounds, Na + , and antioxidant enzymes (CAT, POD, SOD) activities caused by salt stress were attenuated after the exopolysaccharide treatment. GC-MS metabolomics analysis showed that PS treatment allowed the activation and/or inhibition of various metabolic pathways involved in the plant’s tolerance to stress such as jasmonic acid-dependent pathways. This study shows the potential of microalgal exopolysaccharides for enhancing tomato tolerance to salt stress and highlights the possibility of their use as plant growth biostimulants under harsh environmental conditions.