Biotrophic phytopathogenic fungi such as Podosphaera xanthii have evolved sophisticated mechanisms to adapt to various environments causing powdery mildews leading to substantial yield losses. Today, due to known adverse effects of pesticides, development of alternative control means is crucial and can be achieved by combining plant protection products with resistant genotypes. Using plant defense inducers, natural molecules that stimulate plant immune system mimicking pathogen attack is sustainable, but information about their mode of action in different hosts or host genotypes is extremely limited. Reynoutria sachalinensis extract, a known plant defense inducer, especially through the Salicylic acid pathway in Cucurbitaceae crops against P. xanthii, was employed to analyze the signaling cascade of defense activation. Here, we demonstrate that R. sachalinensis extract enhances phospholipid production and signaling in a Susceptible to P. xanthii courgette genotype, while limited response is observed in an Intermediate Resistance genotype due to genetic resistance. Functional enrichment and cluster analysis of the upregulated expressed genes revealed that inducer application promoted mainly lipid- and membrane-related pathways in the Susceptible genotype. On the contrary, the Intermediate Resistance genotype exhibited elevated broad spectrum defense pathways at control conditions, while inducer application did not promote any significant changes. This outcome was obvious and at the metabolite level. Main factor distinguishing the Intermediate Resistance form the Susceptible genotype was the epigenetic regulated increased expression of a G3P acyltransferase catalyzing phospholipid production. Our study provides evidence on phospholipid-based signaling after plant defense inducer treatment, and the selective role of plant’s genetic background.

中文翻译：

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植物防御诱导剂对黄叶 Podosphaera xanthii 的磷脂产生和信号传导是基因型依赖性的


生物营养植物病原真菌，如 Podosphaera xanthii 已经进化出复杂的机制来适应各种环境，导致白粉病，从而导致大量的产量损失。今天，由于农药的已知不利影响，开发替代控制手段至关重要，可以通过将植物保护产品与抗性基因型相结合来实现。使用植物防御诱导剂，刺激植物免疫系统模拟病原体攻击的天然分子是可持续的，但有关它们在不同宿主或宿主基因型中的作用方式的信息极其有限。Reynoutria sachalinensis 提取物是一种已知的植物防御诱导剂，特别是通过葫芦科作物中的水杨酸途径对抗黄花，用于分析防御激活的信号级联。在这里，我们证明 R. sachalinensis 提取物增强了对 P. xanthii 西葫芦基因型敏感的磷脂产生和信号传导，而由于遗传抗性，在中间抗性基因型中观察到有限的反应。上调表达基因的功能富集和聚类分析表明，诱导剂应用主要促进易感基因型中的脂质和膜相关途径。相反，中间抗性基因型在控制条件下表现出升高的广谱防御途径，而诱导剂的应用没有促进任何显着变化。这个结果是显而易见的，并且在代谢物水平上。区分中间抗性与易感基因型的主要因素是表观遗传调节的 G3P 酰基转移酶的表达增加催化磷脂的产生。 我们的研究为植物防御诱导剂处理后基于磷脂的信号传导以及植物遗传背景的选择性作用提供了证据。