Effect of dopamine and progesterone on the physiological and molecular responses of tomato seedlings to drought and salt stress

Abstract

Drought and salt stress are the most common abiotic stresses resulting in yield reduction or complete loss of agricultural production in recent years. Stress mitigation by external biostimulator molecules has been an active research topic recently. Neurotransmitters (NTs) dopamine and progesterone, found in both animal and plant kingdom were shown to take role in plant abiotic and biotic stress defense in limited number of studies. This study investigated the effects of exogenous dopamine and progesterone application in tomato seedlings under drought and salt stress by examining various morphological and physiological parameters (tissue length and weights, relative water content, ion leakage, malondialdehyde and proline levels), as well as expressions of various genes encoding enzymes; superoxide dismutase (FeSOD), catalase (CAT2), glutathione reductase (GR1), ascorbate peroxidase (APX1), 1-aminocyclopropane-1-carboxylic acid synthase (ACS2) and delta 1-pyrroline-5-carboxylate synthase (P5CS), that play a direct role in the antioxidative defense system or measured as stress indicators. The results showed that dopamine and progesterone alleviated drought stress mainly by increasing superoxide dismutase and catalase antioxidative enzyme gene expressions and decreasing ethylene production in tomato seedlings, thereby improving cell membrane integrity and increasing root dry weight. Although morphological and physiological responses of the seedlings were mostly similar under drought and salinity stresses, antioxidative defense enzyme gene expressions were not upregulated under salinity stress, except for the GR1 expression under progesterone treatment.

Keywords:

• Solanum lycopersicum L
• abiotic stress
• dopamine
• progesterone

REVIEWING EDITOR:

• Manuel Tejada, Universidad de Sevillam, Spain

SUBJECTS:

• Agriculture & Environmental Sciences
• Plant Biology
• Plant Biotechnology

Authors’ contributions

Ufuk Celikkol Akcay, Ph.D., designed the experiment, performed all the analyses and prepared the manuscript. Reyhan Gencay and Fatma Zehra Koc were M.S. students in the Department of Agricultural Biotechnology. They performed the analyses under the supervision of Ufuk Celikkol Akcay and revised the manuscript for intellectual content.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All the raw data used in the preparation of the manuscript is available upon request.