The Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany.
Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena, Germany.
Nat Plants. 2018 Mar;4(3):152-156. doi: 10.1038/s41477-018-0106-0. Epub 2018 Feb 19.
The discovery in tomato of systemin, the first plant peptide hormone, was a fundamental change for the concept of plant hormones. Numerous other peptides have since been shown to play regulatory roles in many aspects of the plant life, including growth, development, fertilization and interactions with symbiotic organisms. Systemin, an 18 amino acid peptide derived from a larger precursor protein , was proposed to act as the spreading signal that triggers systemic defence responses observed in plants after wounding or attack by herbivores. Further work culminated in the identification of a leucine-rich repeat receptor kinase (LRR-RK) as the systemin receptor 160 (SR160). SR160 is a tomato homologue of Brassinosteroid Insensitive 1 (BRI1), which mediates the regulation of growth and development in response to the steroid hormone brassinolide. However, a role of SR160/BRI1 as systemin receptor could not be corroborated by others. Here, we demonstrate that perception of systemin depends on a pair of distinct LRR-RKs termed SYR1 and SYR2. SYR1 acts as a genuine systemin receptor that binds systemin with high affinity and specificity. Further, we show that presence of SYR1, although not decisive for local and systemic wound responses, is important for defence against insect herbivory.
在番茄中发现的系统素是第一种植物肽激素，这一发现彻底改变了人们对植物激素的概念。此后，大量其他肽类被证明在植物生长、发育、受精以及与共生生物相互作用的许多方面发挥着调节作用。系统素是一种 18 个氨基酸的肽，由一个较大的前体蛋白衍生而来，被认为是一种扩散信号，能触发植物在受伤或受到草食动物攻击后观察到的系统性防御反应。进一步的研究最终确定了富含亮氨酸重复受体激酶（LRR-RK）作为系统素受体 160（SR160）。SR160 是番茄同源物 Brassinosteroid Insensitive 1（BRI1），它介导了生长和发育的调节，以响应甾体激素油菜素内酯。然而，其他人的研究未能证实 SR160/BRI1 作为系统素受体的作用。在这里，我们证明了系统素的感知依赖于一对称为 SYR1 和 SYR2 的独特 LRR-RK。SYR1 作为一种真正的系统素受体，能与系统素高亲和力和特异性结合。此外，我们还表明，虽然 SYR1 的存在对局部和系统性伤口反应不是决定性的，但对抵御昆虫草食性至关重要。
