Wang Cui-Cui, Meng Lan-Huan, Gao Ying, Grierson Donald, Fu Da-Qi
Fruit Biology Laboratory, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.
School of Biosciences, University of Nottingham, Nottingham, United Kingdom.
Front Plant Sci. 2018 Apr 12;9:437. doi: 10.3389/fpls.2018.00437. eCollection 2018.
Steroidal glycoalkaloids (SGAs) are cholesterol-derived specialized metabolites produced by Solanaceous plant species. They contribute to pathogen defense but are considered as anti-nutritional compounds and toxic to humans. Although the genes involved in the SGA biosynthetic pathway have been successfully cloned and identified, transcription factors regulating this pathway are still poorly understood. We report that silencing tomato light signal transduction transcription factors ELONGATED HYPOCOTYL 5 () and PHYTOCHROME INTERACTING FACTOR3 (), by virus-induced gene silencing (VIGS), altered glycoalkaloids levels in tomato leaves compared to control plant. Electrophoretic mobility shift assay (EMSA) and Chromatin immunoprecipitation (ChIP) analysis confirmed that SlHY5 and SlPIF3 bind to the promoter of target genes of GLYCOALKALOID METABOLISM (), affecting the steady-state concentrations of transcripts coding for SGA pathway enzymes. The results indicate that light-signaling transcription factors HY5 and regulate the abundance of SGAs by modulating the transcript levels of these genes. This insight into the regulation of SGA biosynthesis can be used for manipulating the level of these metabolites in crops.
甾体糖苷生物碱（SGAs）是茄科植物产生的胆固醇衍生的特殊代谢产物。它们有助于抵御病原体，但被认为是抗营养化合物且对人类有毒。尽管参与SGA生物合成途径的基因已被成功克隆和鉴定，但调控该途径的转录因子仍知之甚少。我们报告称，通过病毒诱导的基因沉默（VIGS）使番茄光信号转导转录因子长胚轴5（）和光敏色素相互作用因子3（）沉默后，与对照植株相比，番茄叶片中的糖苷生物碱水平发生了变化。电泳迁移率变动分析（EMSA）和染色质免疫沉淀（ChIP）分析证实，SlHY5和SlPIF3与糖苷生物碱代谢（）靶基因的启动子结合，影响编码SGA途径酶的转录本的稳态浓度。结果表明，光信号转录因子HY5和 通过调节这些 基因的转录水平来调控SGAs的丰度。这种对SGA生物合成调控的见解可用于调控作物中这些代谢产物的水平。
