The Interplay Between the Circadian Clock and Plant Immune Mechanisms

描述(申请人提供)：生物钟对地球上的生物有深远的影响。它通过使有机体的新陈代谢和行为与环境相协调来最大化有机体的适合性。然而，明确证明健身益处的研究很少，其潜在的分子机制也鲜为人知。令人惊讶的发现是，拟南芥的时钟成分CCA1是RPP4介导的对卵菌病原菌Arabidopsidis(HPA)抗性的关键调节因子，这导致了对生物钟之间相互作用的第一次深入研究 和植物免疫机制。这项研究的目标1将集中在利用分子遗传学和系统方法剖析CCA1和抗性蛋白RPP4之间的调节电路。将建立一个数学模型来解释RPP4如何扰乱CCA1介导的防御基因的节律性表达，从而导致感染细胞的程序性细胞死亡和对HPA的抗性。目的2研究生物钟在系统获得性抵抗中的作用，以验证生物钟在免疫反应过程中被重置的假设，从而将资源重新定向到防御和促进细胞存活。植物防御机制和动物先天免疫之间有着惊人的相似之处。生物钟对动物免疫反应的影响也已有报道。然而，由于动物生物钟(中枢和外周)和微生物区系本身的复杂性，深入的研究是具有挑战性的。因此，拟南芥-Hyalperospora的研究除了提供详细的分子机制外，还将在揭示生物钟和免疫之间相互作用的设计原则方面具有很大优势。对植物免疫机制的系统观点将有助于我们设计更好的策略来控制作物病害，减少农药的使用，这些农药对环境和人类健康都是有害的。植物健康一直对人类健康有重大影响，19世纪40年代臭名昭著的爱尔兰土豆饥荒就证明了这一点，这场饥荒是由致病疫霉引起的，它是本研究中使用的HPA的近亲。随着世界人口的爆炸性增长，发展更好、更安全的农业实践不是一种选择，而是一种必然。

DESCRIPTION (provided by applicant): The circadian clock has profound impacts on living organisms on earth. It maximizes the fitness of an organism by enabling it to coordinate metabolism and behavior with its environment. However, studies that unequivocally demonstrate the fitness benefits are scarce and the underlying molecular mechanisms are poorly known. The surprising discovery that the Arabidopsis clock component, CCA1, is a key regulator of RPP4-mediated resistance against the oomycete pathogen Hyaloperonospora arabidopsidis (Hpa) leads to this first in depth study of the interplay between the circadian clock and plant immunity mechanisms. Aim 1 of this study will focus on the dissection of the regulatory circuitry between CCA1 and the resistance protein RPP4 using molecular genetics and systems approaches. A mathematical model will be made to explain how RPP4 perturbs CCA1-mediated rhythmic expression of defense genes resulting in programmed cell death of the infected cell and resistance to Hpa. Aim 2 will investigate the role of the circadian clock in systemic acquired resistance to test the hypothesis that the clock is reset during this immune response to redirect the resource to defense and promote cell survival. There are striking parallels between plant defense mechanisms and animal innate immunity. The influence of the circadian clock on animal immune responses has also been reported. However, in depth studies are challenging because of the inherent complexities of animal circadian clocks (central and peripheral) and of the microflora. Therefore, the proposed Arabidopsis-Hyaloperospora study will have a great advantage in revealing the design principles underline the interplay between the circadian clock and immunity besides providing detailed molecular mechanisms. The system perspectives on plants immune mechanisms will help us design better strategies to control crop disease and reduced the use of pesticides, which are hazardous to the environment and human health. Plant health has always had a significant impact on human health as demonstrated by the infamous Irish potato famine in 1840s, which was caused by Phytophthora infestans, a close relative of Hpa used in this study. With the world population exploding, developing better and safer agricultural practices is not a choice, but a necessity.