Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.
Proc Natl Acad Sci U S A. 2010 Aug 17;107(33):14921-5. doi: 10.1073/pnas.1007568107. Epub 2010 Aug 2.
Among the arsenal of plant-derived compounds activated upon attack by herbivores and pathogens are small peptides that initiate and amplify defense responses. However, only a handful of plant signaling peptides have been reported. Here, we have isolated a 12-aa peptide from soybean (Glycine max) leaves that causes a pH increase of soybean suspension-cultured cell media within 10 min at low nanomolar concentrations, a response that is typical of other endogenous peptide elicitors and pathogen-derived elicitors. The amino acid sequence was determined and was found to be derived from a member of the subtilisin-like protease (subtilase) family. The sequence of the peptide was located within a region of the protein that is unique to subtilases in legume plants and not found within any other plant subtilases thus far identified. We have named this peptide signal Glycine max Subtilase Peptide (GmSubPep). The gene (Glyma18g48580) was expressed in all actively growing tissues of the soybean plant. Although transcription of Glyma18g48580 was not induced by wounding, methyl jasmonate, methyl salicylate, or ethephon, synthetic GmSubPep peptide, when supplied to soybean cultures, induced the expression of known defense-related genes, such as Cyp93A1, Chib-1b, PDR12, and achs. GmSubPep is a unique plant defense peptide signal, cryptically embedded within a plant protein with an independent metabolic role, providing insights into plant defense mechanisms.
在受到草食动物和病原体攻击时被激活的植物衍生化合物中，有一些小肽可以引发和放大防御反应。然而，目前只报道了少数几种植物信号肽。在这里，我们从大豆（Glycine max）叶片中分离出一种 12 个氨基酸的肽，该肽在低纳摩尔浓度下 10 分钟内就能引起大豆悬浮培养细胞培养基的 pH 值升高，这是其他内源性肽激发子和病原体衍生激发子的典型反应。确定了氨基酸序列，发现它来源于枯草杆菌蛋白酶（subtilase）家族的一个成员。该肽的序列位于该蛋白的一个区域，该区域在豆科植物的枯草杆菌蛋白酶中是独特的，在迄今为止鉴定的任何其他植物枯草杆菌蛋白酶中都没有发现。我们将这种肽命名为 Glycine max Subtilase Peptide (GmSubPep)。该基因（Glyma18g48580）在大豆植株所有活跃生长的组织中都有表达。尽管 Glyma18g48580 的转录不受创伤、茉莉酸甲酯、水杨酸甲酯或乙烯利的诱导，但合成的 GmSubPep 肽在供给大豆培养物时，会诱导已知的防御相关基因的表达，如 Cyp93A1、Chib-1b、PDR12 和 achs。GmSubPep 是一种独特的植物防御肽信号，隐藏在具有独立代谢作用的植物蛋白中，为植物防御机制提供了新的见解。
