Cold Plasma Seed Priming Alleviates Salinity Stress in Black Cumin (Nigella sativa L.) by Enhancing Phenolic Content, Essential Oil Biosynthesis, and GPPS Gene Expression

Nikzadeh, Hossein; Parisa, Abdollahi; Ebrahimi, Raheleh; Diyanat, Marjan

doi:10.22034/jmpb.2026.373207.2218

Cold Plasma Seed Priming Alleviates Salinity Stress in Black Cumin (Nigella sativa L.) by Enhancing Phenolic Content, Essential Oil Biosynthesis, and GPPS Gene Expression

Articles in Press

Document Type : Research Article

Authors

¹ Department of Plant Breeding and Biotechnology, SR.C., Islamic Azad University, Tehran, Iran

² Department of Horticultural Science, Agronomy and Biotechnology, SR.C., Islamic Azad University, Tehran, Iran

10.22034/jmpb.2026.373207.2218

Abstract

High salt levels in the growing environment can restrict plant development and reduce the accumulation of secondary metabolites in medicinal species. Although cold plasma (CP) seed priming has been reported to improve plant stress tolerance, its effects on essential oil (EO) biosynthesis and geranyl diphosphate synthase (GPPS) gene expression under salinity stress remain poorly understood in black cumin (Nigella sativa L.). Therefore, this study investigated the effects of CP seed priming (0, 50, and 100 s) on growth, oxidative status, phenolic compounds, EO production, and GPPS expression in black cumin grown under 0, 60, and 120 mM NaCl salinity. Salinity significantly affected plant growth and biochemical traits. Severe salinity (120 mM NaCl) reduced shoot and root dry weight by 40% and 34%, respectively, while increasing H₂O₂ accumulation by 216% compared with the control. In contrast, moderate salinity (60 mM NaCl) enhanced secondary metabolism, increasing EO content by 51%, total flavonoid content by 33%, and GPPS expression by 276%. CP priming reduced salt-induced oxidative damage and improved plant performance. The combination of 60 mM salinity and CP treatment for 100 s resulted in the highest total phenolic content, EO content, and GPPS expression, increasing these traits by 37%, 81%, and 298%, respectively, relative to the control. Principal component analysis revealed strong positive associations among GPPS expression, EO traits, and phenolic compounds. Overall, CP seed priming enhanced salinity tolerance and stimulated terpenoid biosynthesis, highlighting its potential as a sustainable strategy to improve the productivity and phytochemical quality of black cumin under saline conditions.

Keywords