Effects of saline elicitors on saponin production in Agave salmiana plants grown in vitro

Abstract

Agave plants are natives of Mexico and have an important role in the functional food industry. Agave salmiana grows in dry and desert soils, which are high in salt content; however, little is known about its response to saline conditions. In this study, A. salmiana plants grown in vitro were exposed to 0.1, 0.5, and 1.0 mM of salt elicitors, including AlCl3, NaCl, and CoCl2, and saponin synthesis and morphological characteristics were examined. Saponins were identified and quantified in ethanolic extracts using HPLC-ELSD. Root length and number, leaf length and number, and plant fresh weight were evaluated to determine the phenological condition of the plant. The presence of salts at various concentrations did not affect the physiological characteristics of the plant. Moreover, 0.5 mM NaCl induced a higher production of total saponin. Chlorogenin glycoside 1 (CG1) and hecogenin glycoside 1 (HG1) content remained unchanged across treatments. By contrast, CG2 and HG2 concentrations tended to decrease in response to increased concentrations of AlCl3, NaCl, or CoCl2. In vitro salt elicitors could be a feasible tool in the synthesis of specific saponins, without compromising on plant biomass. Our findings can be used in further generation of low saponin agave plants in field for the improvement of fermentation yield.