GAME9 regulates the biosynthesis of steroidal alkaloids and upstream isoprenoids in the plant mevalonate pathway

Pablo D. Cárdenas, Prashant D. Sonawane, Jacob Pollier, Robin Vanden Bossche, Veena Dewangan, Efrat Weithorn, Lior Tal, Sagit Meir, Ilana Rogachev, Sergey Malitsky, Ashok P. Giri, Alain Goossens, Saul Burdman, Asaph Aharoni*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

216 Scopus citations

Abstract

Steroidal glycoalkaloids (SGAs) are cholesterol-derived molecules produced by solanaceous species. They contribute to pathogen defence but are toxic to humans and considered as anti-nutritional compounds. Here we show that GLYCOALKALOID METABOLISM 9 (GAME9), an APETALA2/Ethylene Response Factor, related to regulators of alkaloid production in tobacco and Catharanthus roseus, controls SGA biosynthesis. GAME9 knockdown and overexpression in tomato and potato alters expression of SGAs and upstream mevalonate pathway genes including the cholesterol biosynthesis gene STEROL SIDE CHAIN REDUCTASE 2 (SSR2). Levels of SGAs, C24-alkylsterols and the upstream mevalonate and cholesterol pathways intermediates are modified in these plants. Δ(7)-STEROL-C5(6)-DESATURASE (C5-SD) in the hitherto unresolved cholesterol pathway is a direct target of GAME9. Transactivation and promoter-binding assays show that GAME9 exerts its activity either directly or cooperatively with the SlMYC2 transcription factor as in the case of the C5-SD gene promoter. Our findings provide insight into the regulation of SGA biosynthesis and means for manipulating these metabolites in crops.

Original languageAmerican English
Article number10654
JournalNature Communications
Volume7
DOIs
StatePublished - 15 Feb 2016

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