Analysis of secondary metabolites and their induction by salinity (NaCl) in hairy roots of Lycium humile.

BLANK, TOBIAS; PALCHETTI, MARÍA VIRGINIA; IPARRAGUIRRE, JULIA; PAPENBROCK, JUTTA; REGINATO , MARIANA ANDREA

Congreso; XXXIV Reunión de la Sociedad Argentina de Fisiología Vegetal; 2023

Lycium humile Phil. inhabits extreme saline soils in the Altiplano-Puna region (Central Andes, South America). As one of the most salt-tolerant halophytic Solanaceae, L. humile represents a promising experimental model to study salt tolerance in plants of this family. This species can effectively grow at high NaCl concentrations, at least up to 750 mM NaCl, as well as in the absence of salts in the medium. In this study, stable hairy root (HR) cultures of L. humile were obtained by infection of young seedlings with Rhizobium rhizogenes and the three best growing lines (A, B, and C) were selected and subjected to six different NaCl concentrations. The growth and contents of total phenolics, total flavonoids, and total alkaloids were analyzed. Low salinity (100 mM) significantly decreased the HR growth, in contrast to the response previously observed in the growth of whole plants, which was only affected at concentrations above 750 mM NaCl. This suggests that isolated hairy roots lack certain mechanisms that whole plants have to cope with salt stress. HR line B showed a significant increase in total phenolics and total flavonoids under 190 mM NaCl, compared to both lower NaCl treatments of the same line and 190 mM treatments of the other HR lines. Moreover, HR line B showed a considerable amount of alkaloids without exposure to salinity, comparable to the content found in the roots of greenhouse-grown plants. Further experiments are planned to determine the total alkaloid content in response to salt stress and possibly identify novel interesting plant secondary metabolites.