Momilactones from rice have allelopathic activity, the ability to inhibit growth of competing plants. Transferring momilactone production to other crops is a potential approach to combat weeds, yet a complete momilactone biosynthetic pathway remains elusive. Here, we address this challenge through rapid gene screening in Nicotiana benthamiana, a heterologous plant host. This required us to solve a central problem: diminishing intermediate and product yields remain a bottleneck for multistep diterpene pathways. We increased intermediate and product titers by rerouting diterpene biosynthesis from the chloroplast to the cytosolic, high-flux mevalonate pathway. This enabled the discovery and reconstitution of a complete route to momilactones (>10-fold yield improvement in production versus rice). Pure momilactone B isolated from N. benthamiana inhibited germination and root growth in Arabidopsis thaliana, validating allelopathic activity. We demonstrated the broad utility of this approach by applying it to forskolin, a Hedgehog inhibitor, and taxadiene, an intermediate in taxol biosynthesis (~10-fold improvement in production versus chloroplast expression).

水稻中的莫米内酯具有化感作用，即抑制竞争植物生长的能力。将莫米内酯的生产转移到其他作物上是一种对抗杂草的潜在方法，但完整的莫米内酯生物合成途径仍然难以捉摸。在这里，我们通过对本氏烟草进行快速基因筛选来应对这一挑战，异源植物宿主。这要求我们解决一个核心问题：减少中间体和产品产量仍然是多步二萜途径的瓶颈。我们通过将二萜生物合成从叶绿体改道到胞质高通量甲羟戊酸途径来增加中间体和产物滴度。这使得发现和重建了一种完整的莫米内酯路线（与水稻相比，产量提高了 10 倍以上）。从分离的纯稻内酯乙本塞姆氏烟草中抑制发芽和根生长的拟南芥 拟南芥，验证化感作用。我们通过将其应用于毛喉素（一种刺猬抑制剂）和紫杉二烯（一种紫杉醇生物合成的中间体）（与叶绿体表达相比，产量提高约 10 倍）证明了这种方法的广泛实用性。