Effect of Ethylene and Abscisic Acid on Steroid and Triterpenoid Synthesis in Calendula officinalis Hairy Roots and Saponin Release to the Culture Medium

Abstract

Phytohormones (plant growth regulators) can be applied as efficient elicitors to enhance the productivity of plant in vitro cultures, due to their significance in regulating the plant metabolism and strong influence on plant defense responses. In the present study, the effects of exogenous ethylene (ETY, applied in the form of ethephon as an ethylene-generating agent) and abscisic acid (ABA) on the synthesis of triterpenoids and steroids in Calendula officinalis hairy roots were investigated. ABA appeared to be an efficient elicitor of the biosynthesis of triterpenoid oleanolic acid (almost two-fold) and the release of its glycosides (saponins) to the culture medium (up to 6.6-fold). ETY had only a slight effect on triterpenoid metabolism; instead, it strongly influenced steroid metabolism, leading to profound modifications of the quantitative profiles of these compounds, particularly the ratio of stigmasterol to sitosterol. Both the applied phytohormones influenced the interplay between steroid and triterpenoid biosynthetic pathways, revealing the symptoms of their competition.

Modulation of Steroid and Triterpenoid Metabolism in Calendula officinalis Plants and Hairy Root Cultures Exposed to Cadmium Stress

“…Four fractions were obtained as described by Sykłowska-Baranek et al (2022): (i) esters (Rf, retention factor, of 0.9–1); (ii) free steroids and neutral triterpenoids (Rf of 0.3–0.9); (iii) free triterpenoid acids (Rf 0.2–0.3); and (iv) glycosides (Rf of 0–0.2) [ 28 ]. Fraction (ii) containing free steroids and neutral triterpenoids (alcohols) was directly analyzed using GC–MS, gas chromatography-mass spectrometer (Agilent Technologies 7890A); the triterpenoid acid fraction (iii) was methylated with diazomethane prior to GC-MS analysis as described previously [ 37 ]; the ester fraction (i) was subjected to alkaline hydrolysis to release the steroid core from ester forms; and the glycoside fraction (iv) to acidic hydrolysis to release the aglycones.…”

“…The glycoside fractions obtained from the diethyl ether extracts, evaporated methanol extracts and n-butanol extracts from the culture medium were hydrolyzed by 11% HCl in 80% methanol during 2 h on a heating mantle under reflux [ 28 , 37 ]. Subsequently, the hydrolysates were diluted with distilled water, methanol was evaporated in a rotary evaporator, and the obtained aqueous remnants were extracted 3 times with 40 mL portions of diethyl ether in a separation funnel.…”

Chromosome‐level genome of Entada phaseoloides provides insights into genome evolution and biosynthesis of triterpenoid saponins

“…Stress‐induced responses in plants are triggered by several signalling molecules, including phytohormones such as ABA, ethylene (ETH), JA and SA; redox molecules; Ca 2+ ; ROS and mitogen‐activated protein kinases (Sewelam et al, 2016). Thus, phytohormones can act as efficient enhancers of TS productivity in plants, due to their strong influence on plant defence responses (Markowski et al, 2022). Phytohormone‐induced synthesis of TS has been documented in many legumes (Broeckling et al, 2005; Eswaranandam et al, 2012; Hayashi et al, 2003; Hayashi et al, 2004; Shabani et al, 2009; Tamura et al, 2018).…”

Anti-Cancerous Potential of Polysaccharides Derived from Wheat Cell Culture

“…Cell suspension cultures of soft spring wheat Triticum aestivum of the Kazakhstanskaya 10 variety (provided by Kazakh Research Institute of Agriculture and Plant Growing, Almaty, Kazakhstan) were grown in two types of Murashige and Skoog (MS) [ 37 ] liquid medium (Sigma-Aldrich, St. Louis, MO, USA) as we described before [ 33 ] with the addition of phytohormones which are commonly used in plant biotechnology to regulate morphogenesis and biosynthesis of secondary bioactive metabolites in vitro [ 38 , 39 , 40 , 41 ]: 5.0 mg/L 2,4-D—2,4-dichlorophenoxyacetic acid (Sigma-Aldrich, St. Louis, MO, USA) and 1.0 mg/L ABA—abscisic acid (Sigma-Aldrich, St. Louis, MO, USA).…”