Potential of Zingiber zerumbet endophytic Fusarium oxysporum as biopriming agents to control Pythium mediated soft-rot and optimization of fermentation conditions for cytotoxic metabolite(s) production

• Published in: Journal of plant biochemistry and biotechnology Vol. 32; no. 1; pp. 163 - 173
• Main Authors: Keerthi, D., Harsha, K., Harshitha, K., Nair, Aswati R.
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.03.2023; Springer Nature B.V
• Subjects: Agricultural industry; Antagonism; Anticancer properties; Antitumor activity; Aquatic plants; Bioactive compounds; Biocompatibility; Biomedical and Life Sciences; Cell Biology; Chloroform; Chromatography; Column chromatography; Conidia; Cytotoxicity; Endophytes; Fermentation; Fractionation; Fusarium oxysporum; Herbal medicine; Life Sciences; Medicinal plants; Metabolites; Optimization; Original Article; Plant Biochemistry; Protein Science; Pythium; Receptors; Rhizomes; Silica; Silicon dioxide; Soft rot; Soils; Solvent extraction; Solvents; Toxicity; Umbelliferone; Zingiber zerumbet; Zoospores; Umbelliferone; Cytotoxic; Endophyte
• ISSN: 0971-7811; 0974-1275
• DOI: 10.1007/s13562-022-00793-2

Biosynthetic potential of fungal endophytes from medicinal plants represents an attractive source for discovery of new bioactive metabolites. Present study involved characterizing metabolite(s) of non-pathogenic, endophytic Fusarium oxysporum designated ZzEF 8 which was identified previously from Zingiber zerumbet rhizome to display antagonism towards Pythium myriotylum [62.2 ± 2.58% percent of inhibition (PoI)], an oomycetous phytopathogen of significant economic concern. Efficacy of ZzEF 8 in suppressing soft rot by P . myriotylum was further evaluated by planting ginger rhizomes primed with ZzEF 8 conidial suspension (10 6 conidia/ ml) followed by transplanting the primed rhizome in sterile soil infested with P . myriotylum (10 3 zoospores/g soil). Batch fermentation followed by solvent extraction yielded a dark red solid (0.45 mg/ml) which after fractionation by silica column (500 × 30 mm) chromatography (100–200µ) using chloroform: methanol (8:2) solvent yielded three fractions, F1-3. Validation of inhibitory activity of the fractions by disc diffusion assay identified F2 to exhibit absolute P. myriotylum growth inhibition (100%) while F1 and F3 showed 57.62% and 10.73% inhibition respectively. Further purification of F2 by silica column chromatography (300 × 10 mm) yielded three sub-fractions viz., F2a-c. Further LC/Q –TOF MS-analysis of the three sub-fractions identified F2a to contain umbelliferone (t R 6.93 min) as major metabolite. Batch fermentation under submerged conditions was thence optimized for optimal metabolite production. Evaluation of cytotoxicity of F2a and F2b fractions in HeLa cell lines revealed F2a to display cytotoxic effect with IC 50 value of 57.9 µg/ml. Anti- Pythium activity of ZzEF 8 and anti-cancer activity of ZzEF 8 metabolites identified in present experiments signifies its potential for use in pharmaceutical and agricultural industry.