Colonization of Solanum melongena and Vitis vinifera Plants by Botrytis cinerea Is Strongly Reduced by the Exogenous Application of Tomato Systemin

Plant defense peptides are able to control immune barriers and represent a potential novel<br> resource for crop protection. One of the best-characterized plant peptides is tomato Systemin (Sys)<br> an octadecapeptide synthesized as part of a larger precursor protein. Upon pest attack, Sys interacts<br> with a leucine-rich repeat receptor kinase, systemin receptor SYR, activating a complex intracellular<br> signaling pathway that leads to the wound response. Here, we demonstrated, for the first time,<br> that the direct delivery of the peptide to Solanum melongena and Vitis vinifera plants protects from the<br> agent of Grey mould (Botrytis cinerea). The observed disease tolerance is associated with the increase<br> of total soluble phenolic content, the activation of antioxidant enzymes, and the up-regulation of<br> defense-related genes in plants treated with the peptide. Our results suggest that in treated plants,<br> the biotic defense system is triggered by the Sys signaling pathway as a consequence of Sys interaction<br> with a SYR-like receptor recently found in several plant species, including those under investigation.<br> We propose that this biotechnological use of Sys, promoting defense responses against invaders,<br> represents a useful tool to integrate into pest management programs for the development of novel<br> strategies of crop protection.植物防御肽（Plant defense peptides）可调控植物免疫屏障，是一类极具应用前景的新型作物保护资源。 研究最为透彻的植物肽类之一为番茄系统素（Systemin, Sys），它是一种由更大前体蛋白剪切产生的十八肽（octadecapeptide）。当遭受虫害侵袭时，Sys可与富含亮氨酸重复序列受体激酶（leucine-rich repeat receptor kinase）——系统素受体SYR（systemin receptor SYR）结合，激活复杂的胞内信号通路（intracellular signaling pathway），进而触发伤口响应（wound response）。 本研究首次证实，将该肽直接施用于茄子（Solanum melongena）与葡萄（Vitis vinifera）植株，可使其抵御灰霉病致病菌——灰葡萄孢菌（Botrytis cinerea）的侵染。 经该肽处理的植株所表现出的病害耐受性，与其总可溶性酚类物质含量（total soluble phenolic content）升高、抗氧化酶（antioxidant enzymes）活性激活以及防御相关基因的上调表达（up-regulation）密切相关。 本研究结果表明，在经处理的植株中，Sys可通过与SYR同源受体结合，激活Sys信号通路，进而触发生物防御系统（biotic defense system）；这类SYR同源受体近期已在多个植物物种中被发现，涵盖本研究所涉及的物种。 我们认为，这种通过Sys介导的、可激发植物抵御外来入侵者的生物技术应用手段，可作为一项实用工具整合入害虫综合治理方案（pest management programs），为开发新型作物保护策略提供支撑。