Metal nanoparticles and fungal extracts as efficient enhancers of growth and pharmacologically valuable secondary metabolite production in hairy roots of underutilized ethnomedicinal plant Solanum nigrum L.
摘要
This study aimed to enhance secondary metabolite production from hairy roots of underutilized medicinal plant Solanum nigrum L. through novel elicitation with different metal nanoparticles and fungal extracts. S. nigrum hairy roots were induced using A4 strain of Agrobacterium rhizogenes, and grown in ½ MS liquid medium for biomass proliferation. Of the five selected rhizoclonal lines (SNHR-1, SNHR-2, SNHR-3, SNHR-4, SNHR-5), SNHR-1 and SNHR-4 have been chosen for elicitation based on better growth kinetics over 56 days (d) and production of diosgenin, solasodine, and polyphenols. Best phase for elicitation was found to be after 28-d of hairy root culture, determined through root viability study by microscopic observation and FDA-PI dual staining. Among the nanoparticles, greatest fresh- (5220.96 ± 20.16 mg) and dry-biomass (284.13 ± 5.54 mg) were achieved with 5.0 mg L−1 gold and 10.0 mg L−1 silver nanoparticles; whereas highest bioactive compounds were produced by 15.0 mg L−1 gold, 10.0 mg L−1 silver, and 50.0 mg L−1 zinc-oxide nanoparticles. Among fungal treatments, 0.25% Colletotrichum lindemuthianum extract produced the highest fresh- (5080.12 ± 23.21 mg) and dry-biomass (360.34 ± 3.16 mg), which are over five and three times greater than control. Treatment with 0.25% C. lindemuthianum, 0.1% and 0.25% Fusarium oxysporum, 0.5% Ganoderma sp., and 0.5% Sclerotinia sclerotiorum, produced the highest amounts of diosgenin, solasodine, phenolic acids, and flavonoids. Since, nanoparticles possess enhanced reactivity, and fungal extract components elicit a range of secondary metabolites, going forward these two elicitation approaches can support bioreactor-mediated high-scale secondary metabolite production from hairy roots.