Twin effects of fungal elicitor produced from Alternaria alternata on induced systemic resistance and secondary metabolites production in Catharanthus roseus (L.) G. Don

•Fungal elicitor produced from the culture filtrate of Alternaria alternata is highly efficient in induction of ISR in Catharanthus roseus L. (G.) Don.•Application of fungal elicitor helps to increase both innate immunity and two important secondary metabolite (viz., vinblastine and vincristine) production simultaneously.•Nitric oxide (NO) is the signalling molecule behind this induction process. Catharanthus roseus L. (G.) Don is an ornamental plant with a source of medicinally important secondary metabolites i.e., bis-indole alkaloids. Whereas, Catharanthus provides itself as a single source of two anti-cancerous alkaloids (vinblastine and vincristine). Elicitors are low molecular weight compounds, can able to induce systemic resistance by accelerating the defense related enzymes activity and defense compound production with accumulation of several signalling molecules like NO, JA, SA etc, simultaneously increases the production of secondary metabolites. In present study, fungal elicitors are prepared from the culture filtrate of Alternaria alternata (Fr.) Keissl, where three dilutions (crude, 50% and 1%) are made followed by the autoclave and applied to the detached leaves of C. roseus. Phenol (1.37 fold), flavonoid (1.45 fold) along with defense related enzymes (2 fold, PO; 1.38 fold, PPO; 1.4 fold, PAL; 2.68 fold, β-1,3 glucanase) increases their activity in comparison to control set. NO, the signalling molecule was monitored using biochemical method and fluorescence microscopy. Vinblastine and vincristine content are analysed via biochemically, microscopically and by Liquid chromatography-mass spectrometry (LC–MS) where CFA-crude treated set shows about 1.5 fold increases in vinblastine and vincristine production. The obtained result showed higher NO, defense compounds and secondary metabolites induce a defense response in fungal elicitor treated set.