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

生物体必须能够保护他们的细胞免受活性氧物种(ROS)的损害，ROS是正常新陈代谢或应激生长条件(如饥饿)的副产品。高浓度的ROS会破坏细胞内的生物分子，而较低的ROS浓度可能会作为调节细胞机械的信号。这个项目的主要目标是研究一种新的机制，致病疫霉可以用来感知和响应ROS。致病疫霉是一种臭名昭著的植物病原体，也是卵菌的一员，卵菌是一类经济上重要但研究较少的微生物。卵菌产生一种新的基因表达蛋白质调节剂，其DNA结合区含有半胱氨酸氨基酸。ROS被假设为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，以及在工业微生物或植物中设计基因表达和提高产量的新开关。该项目还将通过将研究与教育相结合，并在少数族裔人口较多的社区进行推广，为STEM领域的学生提供指导和培训。之前对模式动植物中的bZIP转录因子的研究发现，它们的DNA结合结构域中的残基与双螺旋接触，包括所谓的“不变天冬氨酸”。然而，在大约一半的致病疫霉和其他卵菌的bZIP中，这种天冬酰胺被半胱氨酸取代。含有半胱氨酸的新型bZIP的敲除导致对氧化应激的耐受性差，从而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。实验将确定bZIP的靶向启动子基序，bZIP的二聚伙伴，以及半胱氨酸氧化如何影响DNA结合和二聚。氧化还原状态的细胞标记物将bZIP的行为与生长发育过程中发生的事情联系起来。总体而言，这项研究将揭示真核辐射期间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，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.