State Key Laboratory of Green Pesticides, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang 550025, China.
College of Forestry, Guizhou University, Guiyang 550025, China.
Genes (Basel). 2024 Sep 23;15(9):1237. doi: 10.3390/genes15091237.
Plant activators have emerged as promising alternatives to conventional crop protection chemicals for managing crop diseases due to their unique mode of action. By priming the plant's innate immune system, these compounds can induce disease resistance against a broad spectrum of pathogens without directly inhibiting their proliferation. Key advantages of plant activators include prolonged defense activity, lower effective dosages, and negligible risk of pathogen resistance development. Among the various defensive pathways targeted, the salicylic acid (SA) signaling cascade has been extensively explored, leading to the successful development of commercial activators of systemic acquired resistance, such as benzothiadiazole, for widespread application in crop protection. While the action sites of many SA-targeting activators have been preliminarily mapped to different steps along the pathway, a comprehensive understanding of their precise mechanisms remains elusive. This review provides a historical perspective on plant activator development and outlines diverse screening strategies employed, from whole-plant bioassays to molecular and transgenic approaches. We elaborate on the various components, biological significance, and regulatory circuits governing the SA pathway while critically examining the structural features, bioactivities, and proposed modes of action of classical activators such as benzothiadiazole derivatives, salicylic acid analogs, and other small molecules. Insights from field trials assessing the practical applicability of such activators are also discussed. Furthermore, we highlight the current status, challenges, and future prospects in the realm of SA-targeting activator development globally, with a focus on recent endeavors in China. Collectively, this comprehensive review aims to describe existing knowledge and provide a roadmap for future research toward developing more potent plant activators that enhance crop health.
植物激活剂作为传统作物保护化学品的替代品，因其独特的作用模式而备受关注，可用于防治作物病害。这些化合物通过激活植物的固有免疫系统，可以诱导广谱病原体的抗性，而无需直接抑制其增殖。植物激活剂的主要优点包括延长防御活性、降低有效剂量和病原体抗性发展的风险极小。在针对的各种防御途径中，水杨酸 (SA) 信号级联已被广泛探索，导致系统获得性抗性的商业激活剂（如苯并噻二唑）的成功开发，广泛应用于作物保护。虽然许多靶向 SA 的激活剂的作用位点已初步映射到该途径的不同步骤，但对其确切机制仍缺乏全面了解。本综述提供了植物激活剂开发的历史视角，并概述了不同的筛选策略，从全植物生物测定到分子和转基因方法。我们详细阐述了 SA 途径的各个组成部分、生物学意义和调控回路，同时批判性地检查了经典激活剂（如苯并噻二唑衍生物、水杨酸类似物和其他小分子）的结构特征、生物活性和拟议作用模式。还讨论了评估此类激活剂实际应用的田间试验的结果。此外，我们强调了全球范围内靶向 SA 激活剂开发的现状、挑战和未来前景，重点介绍了中国最近的努力。总之，本综述旨在描述现有的知识，并为未来的研究提供路线图，以开发更有效的植物激活剂，增强作物健康。
