DIVYA YADAV, SHRADDHA MISHRA, NEERAJ KHARE* AND SADANAND PANDEY
NIAMST, NIMS University Rajasthan, Jaipur-303 121 (Rajasthan), India
*(e-mail: neerajsnkhare@gmail.com; Mobile: 70735 92400)
(Received: August 13, 2025; Accepted: September 27, 2025)
ABSTRACT
Endophytic fungi associated with medicinal plants represent a valuable but under-explored resource for bioactive metabolites. This study examined fungal endophytes isolated from Rauwolfia serpentina and evaluated their ability to modulate metabolite production and stress responses in vitro. Leaf explants were surface-sterilized and cultured on Murashige and Skoog (MS) medium supplemented with 2,4-D (1.0-3.0 mg/l) and 1 mg/l BAP, with 2.0 mg/l 2,4-D plus 1 mg/l BAP yielding maximal callus induction. Cell-free filtrates pre pared from Aspergillus niger biomass were applied at varying concentrations (0.5-7.5%, v/v) to established callus cultures for 24 h to assess elicitation effects on growth, reserpine accumulation, antioxidant enzyme activity and proline content. Increasing filtrate concentration progressively reduced biomass yet significantly enhanced reserpine levels, with 5% filtrate producing the highest yield in 20-day-old calli. Elicited calli also exhibited elevated superoxide dismutase and catalase activities, along with higher proline accumulation at 10-20 days compared with controls, indicating activation of oxidative stress defenses. These findings highlighted the dual effect of fungal elicitation; growth suppression coupled with secondary metabolite stimulation, and underscored the potential of non-viable microbial elicitors as a safer strategy to enhance high-value alkaloid production in R. serpentina cultures. This work expands understanding of the metabolite-producing capacity of its endophytic community and provides a basis for optimizing elicitation protocols for large-scale applications.
Key words: Rauwolfia serpentina, cell cultures, elicitation, endophytic fungi, reserpine