Novel bZIP Transcription Factors and Redox Biology in the Oomycete Phytophthora Infestans

生物体必须能够保护其细胞免受活性氧（ROS）造成的损害，活性氧是可能作为正常代谢或饥饿等应激生长条件的副产品而产生的化学物质。高浓度的ROS会破坏细胞内的生物分子，而较低水平的ROS可能会作为调节细胞机制的信号。该项目的主要目标是研究致病疫霉可能用于感知和响应ROS的新机制。致病疫霉是一种臭名昭著的植物病原体，也是卵菌纲的一员，卵菌纲是一个经济上重要但研究不足的微生物类群。卵菌产生一种新的基因表达蛋白调节剂，其DNA结合结构域中含有氨基酸半胱氨酸。假设ROS改变半胱氨酸的化学形式，改变蛋白质对基因表达的影响。了解这一过程可能会导致保护作物免受卵菌引起的疾病的新策略，以及工程基因表达和提高工业微生物或植物产量的新开关。该项目还将通过将研究与教育结合起来，并在少数民族人口众多的社区开展外联活动，为STEM领域的学生提供指导和培训。先前对来自模式植物和动物的bZIP转录因子的研究确定了其DNA结合结构域中接触双螺旋的残基，包括所谓的“不变天冬酰胺”。“然而，在致病疫霉和其他卵菌的大约一半的bZIP中，这种天冬酰胺被半胱氨酸取代。新的含半胱氨酸的bZIPs的敲除导致对氧化应激的耐受性差，导致半胱氨酸是影响细胞防御网络的氧化还原开关的命题。这将通过整合蛋白质生物化学、生物信息学、细胞生物学、代谢物分析和分子遗传学的多学科方法进行测试。实验将定义bZIPs靶向的启动子基序，bZIPs的二聚化伴侣，以及DNA结合和二聚化如何受到半胱氨酸氧化的影响。氧化还原状态的细胞标记物将bZIP行为置于生长和发育过程中发生的情况下。总的来说，这项研究将揭示在真核辐射过程中调控机制是如何演变的，并有助于确定影响卵菌生长和发育的途径。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

Organisms must be able to protect their cells from damage caused by reactive oxygen species (ROS), which are chemicals that may arise as a byproduct of normal metabolism or stressful growth conditions such as starvation. High concentrations of ROS can damage biomolecules within cells, while lower levels may serve as signals for regulating the cell's machinery. The principal goal of this project is to study a novel mechanism that Phytophthora infestans may use to perceive and respond to ROS. P. infestans is a notorious plant pathogen and a member of the oomycetes, an economically important but under-studied group of microbes. Oomycetes produce a novel protein regulator of gene expression that contains the amino acid cysteine in its DNA-binding domain. ROS are hypothesized to alter the chemical form of the cysteine, altering the protein's effect on gene expression. Understanding this process may lead to new strategies for protecting crops from disease caused by oomycetes, as well as novel switches for engineering gene expression and increasing yields in industrial microbes or plants. The project will also contribute to the mentorship and training of students in STEM fields by integrating research with education and outreach in communities with high minority demographics.Prior studies of bZIP transcription factors from model plants and animals identified residues in their DNA binding domains that contact the double helix, including a so-called "invariant asparagine." However, in about half of the bZIPs of Phytophthora infestans and other oomycetes this asparagine is replaced by cysteine. Knockdowns of the novel cysteine-containing bZIPs resulted in poor tolerance of oxidative stress, leading to the proposition that the cysteine is a redox switch affecting cellular defense networks. This will be tested by a multidisciplinary approach integrating protein biochemistry, bioinformatics, cell biology, metabolite analysis, and molecular genetics. Experiments will define the promoter motifs targeted by the bZIPs, dimerization partners of the bZIPs, and how DNA binding and dimerization are affected by cysteine oxidation. Cellular markers of the redox state will place bZIP behavior in context with what transpires during growth and development. Overall, the research will reveal how regulatory mechanisms have evolved during the eukaryotic radiation and help define pathways affecting growth and development in oomycetesThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.