Melatonin application enhances salt stress-induced decreases in minerals, betalains, and phenolic acids in beet (Beta vulgaris L.) cultivars

authored by
Nesrin Colak, Ana Slatnar, Aljaz Medic, Hülya Torun, Aynur Kurt-Celebi, Gerald Dräger, Jasmin Djahandideh, Tuba Esatbeyoglu, Faik Ahmet Ayaz
Abstract

Melatonin is a potentially active signaling molecule and plays a crucial role in regulating the growth and development of plants under stress conditions, alleviating oxidative damage, enhancing antioxidant defence mechanisms and regulating ion homeostasis. This study examined the effects of exogenous melatonin application on leaf biomass, ion concentrations, betalains, phenolic acid and endogenous melatonin contents comparing red beet (Beta vulgaris L. ‘Ruby Queen’ and ‘Scarlet Supreme’) and white beet (‘Rodeo’ and ‘Ansa’) cultivars under increasing salinity levels of 50, 150, and 250 mM NaCl. Exogenous melatonin increased salinity-induced reductions in fresh and dry weights and osmotic potential in leaves. Na+ concentrations rose significantly with increasing salinity, but cultivar-specific decreases were observed in K+ and Ca2+ concentrations. Additionally, melatonin application improved betalain, betanin and neobetanin contents induced by salt stress. Furthermore, melatonin application caused salt stress and cultivar-specific changes in phenolic acid contents e.g., ferulic acid, sinapic acid, or m-coumaric acid, in soluble free, ester- and glycoside-conjugated and cell wall-bound forms. In addition, antioxidant enzyme activities and compound contents increased significantly in the beets and were subsequently lowered in a cultivar-specific manner by salt stress + melatonin treatment. The current findings indicate that exogenous melatonin improved plant stress tolerance suppressing reactive oxygen species levels, increasing the antioxidant enzyme activities and compound contents and reducing the levels of Na+, maintaining an ionic homeostasis in the selected red and white sugar beet cultivars. It appears that melatonin application may help improve cultivar-specific salt tolerance by enhancing ion homeostasis and betalain and phenolic acid production levels in beets.

Organisation(s)
Institute of Organic Chemistry
Institute of Food Science and Human Nutrition
Molecular Food Chemistry and Food Development
External Organisation(s)
Karadeniz Technical University
University of Ljubljana
Duzce University
Type
Article
Journal
Physiologia Plantarum
Volume
176
ISSN
0031-9317
Publication date
11.11.2024
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Physiology, Genetics, Plant Science, Cell Biology
Electronic version(s)
https://doi.org/10.1111/ppl.14611 (Access: Closed)