Goupil Pascale, Peghaire Elodie, Benouaret Razik, Richard Claire, Sleiman Mohamad, El Alaoui Hicham, Kocer Ayhan
UMR INRAe 547 PIAF, Université Clermont Auvergne, 63000 Clermont-Ferrand, France.
UMR CNRS 6296 ICCF, Université Clermont Auvergne, 63000 Clermont-Ferrand, France.
J Agric Food Chem. 2020 Dec 30;68(52):15409-15417. doi: 10.1021/acs.jafc.0c05719. Epub 2020 Dec 18.
Plant defense inducers (PDIs) are booming and attractive protection agents designed to immunostimulate the plant to reduce subsequent pathogen colonization. The structure-PDI activity relationships of four flavan-3-ols: Epicatechin (EC), Epigallocatechin (EGC), Epicatechin gallate (ECG), Epigallocatechin gallate (EGCG) and Gallotannic acid (GTA) were investigated in both whole plant and suspension cell systems. ECG, EGCG, and GTA displayed elicitor activities. Their infiltration into tobacco leaves induced hypersensitive reaction-like lesions with topical scopoletin and PR-target transcript accumulations. On the contrary, EC and EGC infiltrations fail to trigger the biochemical changes in tobacco tissues. The tobacco BY-2 cells challenged with ECG, EGCG, or GTA led to alkalinization of the BY-2 extracellular medium while EC and EGC did not trigger any pH variation. This work provides evidence that the esterified gallate pattern is as an essential flavonoid entity to induce plant defense reactions in tobacco. The phytoprotective properties of the esterified gallate-free EC and the esterified gallate-rich GTA were evaluated on the tobacco/ var. () pathosystem. Tobacco treatment with EC did not induce significant protection against compared to GTA which shows antimicrobial properties on and decreases the infection on GTA-infiltrated and -sprayed wild-type leaves. GTA protection was impaired in the transgenic NahG tobacco plants, suggesting that protection was mediated by salicylic acid.
植物防御诱导剂（PDIs）是一类蓬勃发展且颇具吸引力的保护剂，旨在通过免疫刺激植物来减少后续病原体的定殖。在全株植物和悬浮细胞系统中研究了四种黄烷-3-醇：表儿茶素（EC）、表没食子儿茶素（EGC）、表儿茶素没食子酸酯（ECG）、表没食子儿茶素没食子酸酯（EGCG）和没食子单宁（GTA）的结构与PDI活性之间的关系。ECG、EGCG和GTA表现出诱导活性。它们渗入烟草叶片会诱导类似过敏反应的损伤，并伴有局部 scopoletin 和 PR 靶标转录物积累。相反，EC和EGC的渗入未能引发烟草组织中的生化变化。用ECG、EGCG或GTA处理的烟草BY-2细胞导致BY-2细胞外培养基碱化，而EC和EGC未引发任何pH变化。这项工作提供了证据，表明酯化没食子酸模式是诱导烟草植物防御反应的必需类黄酮实体。在烟草/变种（）病理系统上评估了不含酯化没食子酸的EC和富含酯化没食子酸的GTA的植物保护特性。与GTA相比，用EC处理烟草对没有诱导出显著的保护作用，GTA对具有抗菌特性，并减少了在GTA渗入和喷洒的野生型叶片上的感染。在转基因NahG烟草植物中，GTA的保护作用受损，这表明保护作用是由水杨酸介导的。
