Department of Biology, University of Rome Tor Vergata, Rome, Italy.
PhD Program in Cellular and Molecular Biology, Department of Biology, University of Rome "Tor Vergata", Rome, Italy.
Plant Biol (Stuttg). 2024 Dec;26(7):1213-1222. doi: 10.1111/plb.13725. Epub 2024 Sep 27.
Dittrichia viscosa (L.) Greuter, a perennial plant in the Asteraceae, has strong allelopathic activity due to the high content of various secondary metabolites. The bicyclic sesquiterpenoid α-costic acid is the most abundant secondary metabolite of D. viscosa. Its remarkable insecticidal, antiparasitic, and phytotoxic activities point to its potential use as a natural herbicide, but information on its mode of action is lacking. To shed light on the mechanism of action of α-costic acid in plant cells, we investigated the phytotoxicity of α-costic acid in tomato plants (Solanum lycopersicum L.) through in vivo assays, the underlying cellular effects using biochemical assays, and the effect on subcellular organelles using confocal microscopy on tomato protoplasts incubated with organelle-specific fluorescent probes. In vivo tests showed that α-costic acid inhibited the growth of tomato seedlings and induced chlorosis and spot lesions in leaves. Biochemical assays demonstrated that α-costic acid caused ion leakage, chlorophyll depletion, HO overproduction, callose deposition, and membrane lipid peroxidation. Confocal microscopy demonstrated that α-costic acid determined ROS overproduction and network disruption in mitochondria, singlet oxygen overproduction in chloroplasts, vacuole disintegration, and autophagosome formation. Overall, our data are consistent with a model according to which α-costic acid phytotoxicity is related to oxidative stress in mitochondria and chloroplasts that induces extensive membrane damage, ultimately resulting in cell death associated with autophagy.
粘毛矢车菊（L.），菊科多年生植物，由于含有各种次生代谢物，具有很强的化感活性。双环倍半萜 α-柯蒂酸是粘毛矢车菊中最丰富的次生代谢物。其显著的杀虫、驱虫和除草活性表明它可能被用作天然除草剂，但关于其作用机制的信息尚不清楚。为了阐明 α-柯蒂酸在植物细胞中的作用机制，我们通过体内试验研究了 α-柯蒂酸对番茄植物（Solanum lycopersicum L.）的化感毒性，使用生化试验研究了潜在的细胞效应，并用共聚焦显微镜研究了对细胞器的影响在与细胞器特异性荧光探针孵育的番茄原生质体上。体内试验表明，α-柯蒂酸抑制番茄幼苗生长，并诱导叶片黄化和斑点病变。生化试验表明，α-柯蒂酸导致离子泄漏、叶绿素耗竭、HO 过量产生、胼胝质沉积和膜脂过氧化。共聚焦显微镜显示，α-柯蒂酸导致线粒体中 ROS 过量产生和网络破坏，叶绿体中单线态氧过量产生，液泡解体和自噬体形成。总的来说，我们的数据与一个模型一致，即 α-柯蒂酸的化感毒性与线粒体和叶绿体中的氧化应激有关，这会导致广泛的膜损伤，最终导致与自噬相关的细胞死亡。
