Plant secondary metabolites production is increased in response to both biotic and abiotic elicitors. This study investigates the impact of sodium nitroprusside (SNP) and Trichoderma harzianum on the molecular and biochemical characteristics of Catharanthus roseus cell suspensions. A leaf cell suspension cultured on a medium supplemented with 8 μM 2,4-D and 2 μM BAP was exposed to Trichoderma harzianum (1% v/v) and SNP (150 μM), and subsequently harvested at 12, 24, 48, and 72 h intervals. The highest catalase, ascorbate peroxidase, β (1–3) glucanase, and chitinase activities were recorded 48-hours after elicitation, and coincided with the highest expression levels of G10H (2.5-fold), T16H (1.5-fold), D4H (1.1-fold), DAT (1.9-fold), STR (5-fold), and CrPRX (2-fold) genes. A positive correlation was established between enzyme activities, Terpenoid Indole Alkaloid (TIAs) biosynthesis pathway genes, and the accumulation of vinblastine and vincristine. HPLC analyses showed that the amount of vinblastine and vincristine increased 1.84 and 1.93-fold, respectively, confirming that fungal extracts and SNP elicitors for 48 h significantly increased the vinblastine and vincristine accumulation and related biosynthesis gene in C. roseus plant.
