Ascorbic Acid Nanoparticles Play a Role in Promoting Salinity Resistance in Catharanthus roseus plants.

Catharanthus roseus is a known therapeutic herb that possesses many terpenoid indole alkaloids. Salt stress is one of the environmental stressors which impact plants productivity, A range of solutions have been developed to combat the damaging impacts of salt stress. This study examined the impact of ascorbic acid (ASC) in both bulk and nanoform at concentrations of 0.05 and 0.1 mM on the salt stress resistance of Catharanthus roseus plants. At both levels, ascorbic acid (ASC) and ascorbic acid nanoparticles (ASC-NPs) suppressed the impacts of salinity on Catharanthus roseus plants. Plant height, biomass, and plant weights all rose significantly in response to 0.1 mM ASC-NPs. Furthermore, ASC-NPs (0.1 mM) treatment increased chlorophyll and carotenoid concentration in plant leaves. In response to ASC -NPs at 0.1mM, catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) activity increased to their greatest levels. The WRKY40 gene reached the highest expression level (58.89-fold increase) in C. roseus plants in response to salinity and 0.1 mM ASC-NPs treatment compared to the control. According to qRT-PCR data, WRKY1, WRKY2, and MYC2 genes were downregulated following treatment application, in comparison to the control, except for 0.1 mM ASC-NPs under salt stressor (150 mM NaCl), where the expression of LEA and MAPK6 genes increased (2.93-fold) above the control.