Multi-omics assisted characterization of GuMYB30 in nodulated Glycyrrhiza uralensis for flavonoid biosynthesis

Glycyrrhiza uralensis Fisch is a legume of significant economic and medicinal value. As a nitrogen-fixing legume, G. uralensis forms root nodules that convert atmospheric nitrogen into high-quality nitrogen readily absorbed by plants. How nodulation affects the production of characteristic flavonoids (CFs) in G. uralensis remains poorly understood. In this study, a total of 268 differentially accumulated metabolites (DAMs) were identified in nodulated G. uralensis roots, including flavonoids and terpenoid compounds. Transcriptomic profiling revealed 3350 differentially expressed genes (DEGs), encompassing structural genes and transcription factors implicated in flavonoid biosynthesis. The transcriptomic profiling of nodulated G. uralensis roots identified key structural genes involved in flavonoid biosynthesis that exhibit differential expression. To further investigate the regulatory mechanisms, key transcription factors regulating flavonoids were identified by co-expression analysis in the nodulated roots of G. uralensis. Notably, overexpression of GuMYB30 in G. uralensis roots significantly enhanced the levels of CFs, including liquiritigenin, isoliquiritigenin, liquiritin, isoliquiritin, neoliquiritin, isoliquiritin apioside, and echinatin. This research explores the impact of symbiotic nitrogen fixation (SNF) on distinctive secondary metabolites in a medicinal legume species and contributes to the theoretical framework of plant-microbe interactions.