Mutual interactions between biological timing and innate immunity in Arabidopsis

我们将研究两种不同的信号网络的相互作用，这两种信号网络都有助于植物的表现：内源性时钟系统可以使植物生理学与环境中光照和黑暗的周期性变化保持最佳一致，并通过这些手段促进植物的适应性，先天免疫系统为植物提供防御入侵病原体的策略。在哺乳动物和苍蝇中已经报道了一些昼夜节律性和先天免疫之间相互作用的病例。我们最近观察到，拟南芥中的一个从振子成分是先天免疫系统的一部分，这表明在高等植物中也存在密切的相互作用。此外，拟南芥的昼夜转录组包括参与病原体防御的基因。我们将从两个方向解决这种功能联系。我们将研究病原体挑战对昼夜节律的影响。首先，我们将测试病原体相关分子模式（PAMPs）的影响以及随后细菌感染的影响，使用选定的时钟控制转录本的振荡作为昼夜节律读数。相反，我们将分析内源性定时系统受损对植物免疫反应的影响。将测试一系列突变体和转基因植物对PAMPs的反应，以及细菌感染后疾病症状的发展和存活。这些实验将在多大程度上揭示昼夜节律系统对植物免疫的贡献。这可能是一个完整的生物钟对植物性能的额外好处。

We will investigate the interdigitation of two distinct signaling networks that both contribute to plant performance: The endogenous clock system serves to optimally align plant physiology to the periodic changes of light and darkness in the environment and by these means contributes to fitness of the plant, and the innate immune system provides strategies to the plant for self-defense against invading pathogens. A few cases of mutual interactions between circadian rhythmicity and innate immunity have been reported in mammals and flies. Our recent observation that a slave oscillator component in Arabidopsis thaliana is part of the innate immune system suggests a close interaction also in higher plants. Moreover, the circadian transcriptome of Arabidopsis comprises genes involved in pathogen defense. We will address this functional connection from both directions. We will investigate the impact of pathogen challenge on circadian rhythms. First we will test the influence of pathogenassociated molecular patterns (PAMPs) and subsequently the effect of bacterial infection, using the oscillation of selected clock-controlled transcripts as a circadian readout. Conversely, we will analyse the consequences of an impaired endogenous timing system on plant immune responses. A suite of mutants and transgenic plants disrupted in selected components of the circadian system will be tested for their responses to PAMPs and for disease symptom development and survival upon bacterial infection. These experiments will provide insights to what extent the circadian system contributes to plant immunity. This may emerge as an additional benefit of an intact circadian clock for plant performance.