Fungal endophytes Fusarium solani SGGF14 and Alternaria tenuissima SGGF21 enhance the glycyrrhizin production by modulating its key biosynthetic genes in licorice (Glycyrrhiza glabra L.).

This article focuses on the identification and characterization of fungal endophytes from Glycyrrhiza glabra L. (licorice) rhizomes that produce glycyrrhizin and enhance its content in the host plant. Two isolates, SGGF14 (Fusarium solani) and SGGF21 (Alternaria tenuissima), were found to produce glycyrrhizin in culture and, when inoculated into endophyte-free G. glabra plants, increased glycyrrhizin content by 133%–171% compared to controls. This enhancement correlated with upregulated expression of key glycyrrhizin biosynthetic genes (SQS1, SQS2, CYP88D6, and CYP72A154), while genes related to other pathways (LUS and CAS) were downregulated. Although natural control plants harboring native endophytes showed better overall growth than inoculated or endophyte-free plants, the study highlights the potential of specific fungal endophytes as bioactive metabolite producers and modulators of secondary metabolism in licorice.