Huda Enaya Mahood

Phoenix dactylifera L. known as date palm is a precious horticultural cash crop for arid and semi-arid regions, and an important medicinal plant rich in bioactive compounds (phenolics, flavonoids, antioxidants). Tissue culture remains an eco-friendly biotechnological technique to provide quality-planting propagules and sustainable synthesis of phytochemicals and plant biomass using elicitation as a highly efficacious strategy approach. In this framework, various concentrations (25, 50, 100, 200, and 400 mg/L) of Fusarium oxysporum Schlecht. as a biotic elicitor in callus cultures of P. dactylifera were tested. Results revealed that callus biomass yield, total phenolic content (TPC), total flavonoid content (TFC), and bioactive compound levels were found significantly elevated under the effect of fungal elicitation, irrespective of concentration as compared with the non-elicited control treatment. The findings demonstrated that the optimum fresh weight (FW) (1215.8 mg), dry weight (DW) (628.3 mg), TPC [209.6 mg gallic acid equivalents (GAE)/100 g DW), total phenolic production (131712.6 mg/L), TFC (96.2 mg quercetin equivalent (QE)/100 g DW), total flavonoid production (60463.4 mg/L), accumulation of apigenin (32.1 mg/g), caffeic acid (25.8 mg/g) and catechin (24.1 mg/g DW) as phenolic compounds as well as kaempferol (16.9 mg/g), quercetin (15.6 mg/g) and rutin (14.8 mg/g DW) as flavonoid compounds, were achieved when date palm callus cultures were incubated with 50 mg/L F. oxysporum as an elicitor for 30 days. The outcomes of this study could be of great usefulness in the nutraceutical and agronomic industries, facilitating the further development of large-scale production of polyphenols and the utilization of bioreactors.

The belladonna plant, Atropa belladonna L. (Solanaceae), is the most important commercial source of tropane alkaloids such as atropine and scopolamine used for medicinal and pharmaceutical purposes. The chemical biosynthesis and extraction of tropane alkaloids using wild-collected plants has been demonstrated to be difficult, prolong and commercially unachievable. Therefore, this study investigated the combinational impact of different (1) leaf sterilization treatments [mercuric chloride ( HgCl2) (0.1–0.3%), sodium hypochlorite (NaOCl) (20–40%), thiophanate-methyl (fungicide) (10–30%)] on viability, clean explants, and contamination %, (2) 2-isopentenyladenine (2-iP) (2–3 mg/L) + 2,4-dichlorophenoxyacetic acid (2,4-D) (2–6 mg/L) on callus induction % and fresh weight (FW), and (3) 2-iP + 2,4-D + 1–3 mM ornithine on dry weight (DW), atropine and scopolamine content in in vitro cell suspension cultures of A. belladonna. The 0.1% HgCl2 + 30% thiophanatemethyl + 40% NaOCl sterilization treatment was the most effective (100% disinfection, 70% viability). Maximized callus induction (100%) and FW were recorded in MS medium containing 3 mg/L 2-iP + 2 mg/L 2,4-D (4 weeks) and 2 mg/L 2-iP + 5 mg/L 2,4-D (2 months), respectively. DW and scopolamine (4.33 mg/g), and atropine (4.14 mg/g) content were higher in liquid medium with 3 mg/L 2-iP + 3 mg/L 2,4-D + 1 or 3 mM ornithine, respectively (10 weeks). In vitro production of atropine and scopolamine in cell suspension cultures of A. belladonna in shake flasks can be increased and accelerated using elicitors such as plant growth regulators (i.e., 2-iP, 2,4-D) and amino acids precursors (i.e., ornithine) involved in alkaloids biosynthetic pathway.