Investigation of the effects of exogenously applied cysteine on gökçe and küsmen chickpea varieties under salt stress

Salt stress is a significant abiotic factor that damages cell membranes, limiting plant growth and development. This study investigated the mitigating role of exogenously applied cysteine (Cys) on the adverse effects of salt stress in chickpea (Cicer arietinum L.) varieties Gökçe (salt-tolerant) and Küsmen (salt-sensitive). In the study, seedlings were treated with 100 µM Cys for 2 days, followed by the application of 100 mM sodium chloride (NaCl) for 5 days to induce salt stress. Salt-stressed plants showed reductions in shoot biomass and water content; however, Cysteine application alleviated these adverse effects. Cysteine treatment reduced lipid peroxidation while increasing levels of total sugars, polyamines, and proline. It also enhanced stomatal opening and leaf area. Antioxidant enzyme activities (superoxide dismutase, catalase, ascorbate peroxidase) were elevated, and Cysteine supported osmolyte accumulation by upregulating the expression of arginine decarboxylase (ADC), proline 5-carboxylate synthase (P5CS), trehalose-6-phosphate dehydrogenase (T6P), and catalase (CAT) genes. In conclusion, cysteine mitigated the detrimental effects of salt stress in chickpea plants, with a more pronounced effect observed in the Küsmen variety. Cysteine was determined to be an effective stress-relieving agent that enhances antioxidant defense and osmoregulatory systems.