Trdá Lucie, Janda Martin, Macková Denisa, Pospíchalová Romana, Dobrev Petre I, Burketová Lenka, Matušinsky Pavel
Laboratory of Pathological Plant Physiology, Institute of Experimental Botany of The Czech Academy of Sciences, Prague, Czechia.
Laboratory of Plant Biochemistry, Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Prague, Czechia.
Front Plant Sci. 2019 Nov 28;10:1448. doi: 10.3389/fpls.2019.01448. eCollection 2019.
Being natural plant antimicrobials, saponins have potential for use as biopesticides. Nevertheless, their activity in plant-pathogen interaction is poorly understood. We performed a comparative study of saponins' antifungal activities on important crop pathogens based on their effective dose (EC) values. Among those saponins tested, aescin showed itself to be the strongest antifungal agent. The antifungal effect of aescin could be reversed by ergosterol, thus suggesting that aescin interferes with fungal sterols. We tested the effect of aescin on plant-pathogen interaction in two different pathosystems: versus (fungus) and versus (bacterium) pv DC3000 ( DC3000). We analyzed resistance assays, defense gene transcription, phytohormonal production, and reactive oxygen species production. Aescin activated defense through induction of the salicylic acid pathway and oxidative burst. This defense response led finally to highly efficient plant protection against that was comparable to the effect of fungicides. Aescin also inhibited colonization of by DC3000, the effect being based on active elicitation of salicylic acid (SA)-dependent immune mechanisms and without any direct antibacterial effect detected. Therefore, this study brings the first report on the ability of saponins to trigger plant immune responses. Taken together, aescin in addition to its antifungal properties activates plant immunity in two different plant species and provides SA-dependent resistance against both fungal and bacterial pathogens.
作为天然植物抗菌剂，皂苷有作为生物农药的潜力。然而，它们在植物与病原体相互作用中的活性却鲜为人知。我们基于有效剂量（EC）值对皂苷对重要作物病原体的抗真菌活性进行了比较研究。在所测试的皂苷中，七叶皂苷表现为最强的抗真菌剂。七叶皂苷的抗真菌作用可被麦角固醇逆转，因此表明七叶皂苷会干扰真菌固醇。我们在两种不同的病理系统中测试了七叶皂苷对植物与病原体相互作用的影响：与（真菌）相比以及与（细菌）丁香假单胞菌番茄致病变种（Pst）DC3000（Pst DC3000）相比。我们分析了抗性测定、防御基因转录、植物激素产生和活性氧产生。七叶皂苷通过诱导水杨酸途径和氧化爆发激活了拟南芥的防御。这种防御反应最终导致对Pst的高效植物保护，其效果与杀菌剂相当。七叶皂苷还抑制了Pst DC3000对拟南芥的定殖，其作用基于对水杨酸（SA）依赖性免疫机制的积极诱导，且未检测到任何直接的抗菌作用。因此，本研究首次报道了皂苷触发植物免疫反应的能力。综上所述，七叶皂苷除了具有抗真菌特性外，还能在两种不同的植物物种中激活植物免疫，并提供对真菌和细菌病原体的SA依赖性抗性。
