Development of a Cell Suspension Culture System for Promoting Alkaloid and Vinca Alkaloid Biosynthesis Using Endophytic Fungi Isolated from Local Catharanthus roseus

Cell and tissue cultures of Catharanthus roseus have been studied extensively as an alternative strategy to improve the production of valuable secondary metabolites. The purpose of this study was to produce C. roseus callus and suspension cell biomass of good quality and quantity to improve the total alkaloids and bis-indole alkaloids. The young stem derived-callus of C. roseus variety Quang Ninh (QN) was grown on MS medium supplemented with 1.5 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) plus 1.5 mg/L kinetin, and the growth rate increased by 67-fold after 20 days. The optimal conditions for maintaining the cell suspension culture were 150 mg/50 mL cell inoculum, a medium pH of 5.5 and a culture temperature of 25 °C. The low alkaloid content in the culture was compensated for by using endophytic fungi isolated from local C. roseus. Cell extracts of endophytic fungi—identified as Fusarium solani RN1 and Chaetomium funicola RN3—were found to significantly promote alkaloid accumulation. This elicitation also stimulated the accumulation of a tested bis-indole alkaloid, vinblastine. The findings are important for investigating the effects of fungal elicitors on the biosynthesis of vinblastine and vincristine, as well as other terpenoid indole alkaloids (TIAs), in C. roseus QN cell suspension cultures.