Plants are known to develop a multi-faceted innate immune system for pathogenic defense. Systemic acquired resistance (SAR) and induced systemic resistance (ISR) are the two main pathways. Many chemical inducers known as plant activators that activate innate immunity to defend against pathogens have been discovered. Currently, the exploitation of new plant activators is mainly done to develop analogs of salicylic acid as SAR-signaling molecules; however, the ISR pathway is hardly investigated for new plant activators. Based on recent studies on 1-methyl pyrazolo [3,4-d]pyrimidine bioactivity and ATP-induced resistance to biotrophic and necrotrophic pathogens, a new lead compound, 1-methyl-4-amino-pyrazolo [3,4-d]pyrimidine, was obtained as a new scaffold of plant activators for possible inducing ISR immunity system. Additionally, fluorine atom plays an important role in the design and development of new pesticides due to the unique physical chemistry effect, a series of pyrazolo [3,4-d]pyrimidine derivatives were designed and synthesized. Several compounds showed good broad-spectrum induced resistance in vivo, but there was no direct antibacterial activity in vitro. Notably, the introduction of fluorine atom at the para-position of the benzene ring greatly enhanced the induction activity of P1d both involved in SAR and ISR pathways, which implied the inducing resistance both in defending pathogens and insects.

中文翻译：

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氟-吡唑并[3,4-d]嘧啶衍生物作为一种新型植物激活剂诱导双通路免疫系统

众所周知，植物会发展出多方面的先天免疫系统以进行病原防御。系统性获得性耐药（SAR）和诱导性系统性耐药（ISR）是两种主要途径。已经发现了许多被称为植物激活剂的化学诱导剂，它们激活先天免疫以抵御病原体。目前，新植物活化剂的开发主要是开发水杨酸类似物作为SAR信号分子；然而，对于新的植物激活剂，几乎没有研究 ISR 途径。基于最近对 1-甲基吡唑并 [3,4-d] 嘧啶生物活性和 ATP 诱导的对生物营养和坏死性病原体的抗性的研究，一种新的先导化合物，1-甲基-4-氨基-吡唑并 [3,4-d]嘧啶是作为植物激活剂的新支架，用于可能诱导 ISR 免疫系统。此外，氟原子由于其独特的物理化学效应在新型农药的设计和开发中发挥着重要作用，设计合成了一系列吡唑并[3,4-d]嘧啶衍生物。几种化合物在体内表现出良好的广谱诱导抗性，但在体外没有直接的抗菌活性。值得注意的是，在苯环对位引入氟原子极大地增强了参与SAR和ISR途径的P1d的诱导活性，这意味着在防御病原体和昆虫方面的诱导抗性。但在体外没有直接的抗菌活性。值得注意的是，在苯环对位引入氟原子极大地增强了参与SAR和ISR途径的P1d的诱导活性，这意味着在防御病原体和昆虫方面的诱导抗性。但在体外没有直接的抗菌活性。值得注意的是，在苯环对位引入氟原子极大地增强了参与SAR和ISR途径的P1d的诱导活性，这意味着在防御病原体和昆虫方面的诱导抗性。