Yeast extract elicitation enhances growth and metabolite production in Limonium algarvense callus cultures

Abstract Limonium algarvense Erben, a medicinal halophyte, holds significant pharmacological promise due to its rich bioactive compound repertoire. This study aimed to establish robust callus cultures as a sustainable, in vitro model for studying the plant's metabolic responses, particularly focusing on synthesising and accumulating primary and secondary metabolites under various elicitation treatments. Callus cultures were initiated from leaf explants on Murashige and Skoog's medium supplemented with 1 mg/L picloram for 4 weeks. Afterwards, callus cultures were subjected to two elicitor treatments, including salicylic acid–SA and yeast extract–YE at 50 and 100 mg/L for four weeks. Water extracts were assessed for their shifts in primary (total soluble sugars and proteins, and proline), and secondary metabolism (total phenolics, flavonoids, and condensed tannins). In addition, a detailed metabolic profiling was conducted using high-performance liquid chromatography with electrospray ionisation mass spectrometry (HPLC–ESI–MS/MS). Elicitation induced significant shifts in the metabolite synthesis of elicited cultures compared to controls. While YE50 markedly increased the callus yield, the total levels of phenolics, flavonoids condensed tannins and total soluble proteins, the SA50 led to the highest increase in proline content. Metabolomic analysis identified 10 metabolites, including 4-hydroxyphenyllactic acid, hydroxybenzoic acid, riboflavin (Vitamin B2), and dihydroferulic acid methyl ester 4-O-sulfate, that were increased in the YE50 elicitation treatment. This suggests that elicitation can effectively enhance the biosynthesis of primary and secondary metabolites in L. algarvense callus cultures, offering great potential for nutritional and medicinal applications.