类固醇生物碱(SGA)是由数百种茄属物种产生的专门代谢产物,包括重要的蔬菜作物,如番茄,土豆和茄子.尽管SGA因其在植物防御中的作用和“抗营养”作用而闻名(例如,毒性和苦味)对人类,这些分子中的许多都有抗癌记录,抗微生物,抗炎,抗病毒和解热活性。其中,从黑色茄属植物(Solanumnigrum)中分离出的α-solasonine和α-solamargine,据报道具有有效的抗肿瘤作用,抗增殖和抗炎活性。值得注意的是,α-solasonine和α-solamargine,与核心甾体糖苷配基solasodine一起,是茄属植物中产生的最广泛的SGA。然而,目前还不清楚植物如何合成这些生物活性甾体分子。通过比较代谢组-转录组指导方法,生物合成逻辑,烟草中的组合表达和功能重组酶测定,在这里,我们报告了来自黑草的12种酶的发现,这些酶将起始胆固醇前体转化为solasodine糖苷配基,和下游的α-solasonine,α-茄精和丙二酰-茄精SGA产品。我们进一步从栽培茄子中鉴定了6种催化α-solasonine产生的酶,来自solasodine糖苷配基的α-solamargine和丙二酰-solamargineSGAs,通过糖基化和非典型丙二酰修饰。我们的工作为高价值的工程生产提供了基因工具箱和平台,使用合成生物学在异源宿主中的甾体生物活性分子。
Steroidal glycoalkaloids (SGAs) are specialized metabolites produced by hundreds of Solanum species, including important vegetable crops such as tomato, potato, and eggplant. Although it has been known that SGAs play important roles in defense in plants and \"anti-nutritional\" effects (e.g., toxicity and bitterness) to humans, many of these molecules have documented anti-cancer, anti-microbial, anti-inflammatory, anti-viral, and anti-pyretic activities. Among these, α-solasonine and α-solamargine isolated from black nightshade (Solanum nigrum) are reported to have potent anti-tumor, anti-proliferative, and anti-inflammatory activities. Notably, α-solasonine and α-solamargine, along with the core steroidal aglycone solasodine, are the most widespread SGAs produced among the Solanum plants. However, it is still unknown how plants synthesize these bioactive steroidal molecules. Through comparative metabolomic-transcriptome-guided approach, biosynthetic logic, combinatorial expression in Nicotiana benthamiana, and functional recombinant enzyme assays, here we report the discovery of 12 enzymes from S. nigrum that converts the starting cholesterol precursor to solasodine aglycone, and the downstream α-solasonine, α-solamargine, and malonyl-solamargine SGA products. We further identified six enzymes from cultivated eggplant that catalyze the production of α-solasonine, α-solamargine, and malonyl-solamargine SGAs from solasodine aglycone via glycosylation and atypical malonylation decorations. Our work provides the gene tool box and platform for engineering the production of high-value, steroidal bioactive molecules in heterologous hosts using synthetic biology.