环棕榈酸是西兰属真菌病原菌产生的主要植物毒性代谢产物之一,因果代理,其中,柏科植物的溃疡病。先前的研究表明,代谢物可以部分再现感染的症状,并且对不同的植物物种有毒,从而证明是非特异性植物毒素。尽管该化合物具有显著的生物学效应,这也揭示了杀虫,杀真菌和除草特性,有关其行动方式的信息仍然缺乏。在这项研究中,我们研究了环帕酸在拟南芥植物和原生质体中的作用,以获得有关亚细胞靶标和作用机制的信息。生化检测结果表明,环帕酸诱导叶片萎黄病,离子泄漏,膜-脂质过氧化,过氧化氢生产,抑制体内根质子挤压和体外质膜H-ATPase活性。qRT-PCR实验表明,该毒素引发了对坏死真菌免疫应答的关键调节因子的转录,激素的生物合成,以及与衰老和程序性细胞死亡有关的基因。原生质体的共聚焦显微镜分析可以解决毒素的亚细胞靶标的问题。环棕榈酸靶向质膜H+-ATP酶,诱导跨膜电位的去极化,线粒体,破坏线粒体网络并引起活性氧的过量产生,和液泡,确定液泡膜分裂和诱导液泡介导的程序性细胞死亡和自噬。
Cyclopaldic acid is one of the main phytotoxic metabolites produced by fungal pathogens of the genus Seiridium, causal agents, among others, of the canker disease of plants of the Cupressaceae family. Previous studies showed that the metabolite can partially reproduce the symptoms of the infection and that it is toxic to different plant species, thereby proving to be a non-specific phytotoxin. Despite the remarkable biological effects of the compound, which revealed also insecticidal, fungicidal and herbicidal properties, information about its mode of action is still lacking. In this study, we investigated the effects of cyclopaldic acid in Arabidopsis thaliana plants and protoplasts, in order to get information about subcellular targets and mechanism of action. Results of biochemical assays showed that cyclopaldic acid induced leaf chlorosis, ion leakage, membrane-lipid peroxidation, hydrogen peroxide production, inhibited root proton extrusion in vivo and plasma membrane H+-ATPase activity in vitro. qRT-PCR experiments demonstrated that the toxin elicited the transcription of key regulators of the immune response to necrotrophic fungi, of hormone biosynthesis, as well as of genes involved in senescence and programmed cell death. Confocal microscopy analysis of protoplasts allowed to address the question of subcellular targets of the toxin. Cyclopaldic acid targeted the plasma membrane H+-ATPase, inducing depolarization of the transmembrane potential, mitochondria, disrupting the mitochondrial network and eliciting overproduction of reactive oxygen species, and vacuole, determining tonoplast disgregation and induction of vacuole-mediated programmed cell death and autophagy.