Decoding Steroid-Derived Metabolite Engineering in Solanum

Abstract

Steroidal glycoalkaloids (SGAs) and steroidal saponins (STSs) play significant role in the plant defense against pests and offer various pharmaceuticals applications. SGAs and STSs generally share common biosynthetic pathways in Solanum, originating from a furostanol scaffold. Despite the discovery of multiple GLYCOALKALOID METABOLISM (GAME) genes involved in the biosynthesis of these compounds, previous attempts for the metabolic engineering of these pathways have remained unsuccessful. The GAME15 protein, with its dual enzymatic roles, has unlocked a mystery surrounding the intricate process of metabolizing cholesterol. This protein not only acts as a glucuronosyltransferase but also serves as a metabolic scaffold, organizing several proteins for the proper functioning. This mini review briefly describes the molecular mechanisms and functional dynamics of GAME genes, particularly focusing on GAME15 as a key game changer gene and its role in metabolite channeling, regulation of pathway, and ecological importance. We highlighted the potential of this discovery for advancing metabolic engineering in crop improvement and the pharmaceutical industry. This finding opens doors for designing crops that are resistant to pests. Additionally, we identify important future research directions, including the regulatory mechanisms of these pathways and uncovering structural aspects of pivotal enzymes.