CAREER: Understanding the function and regulation of amino acid transporters in plant innate immunity

植物是非常有弹性的生物体，能够感知并适应性地应对挑战，包括不断尝试使用它们所拥有的资源的各种微生物。了解植物如何实现对微生物感染的持久和广泛抵抗力，有望揭示增强作物和生态重要植物物种对微生物疾病的抵抗力的新方法，这是一项重大挑战，因为预计到2050年将有90亿人需要食物和健康的栖息地。目前的研究旨在了解植物如何应对微生物入侵者以限制感染。在叶片间隙中繁殖的细菌微生物从植物宿主那里获得它们所需的所有代谢物和营养物质。因此，了解植物如何调节叶间隙空间的组成将允许更广泛的理解-和潜在的发现-植物抵抗感染的方式。此外，拟议的研究将提供K-12教师培训与研究经验，从而促进长期的研究合作，从大学延伸到弗吉尼亚州地区的公立学校。通过这一点，所提出的研究将使数百名高中生接触到以探究为基础的开放式实验，以促进高阶思维技能。虽然少数适应性强的微生物能够感染目标植物并引起疾病，但大多数植物对大多数病原体具有抗性。这种广谱抗性部分归因于微生物相关分子模式（MAMP）的感知和随后引发的抑制微生物生长的MAMP触发免疫（MTI）。虽然MAMP激活的植物信号程序越来越好地理解，植物限制微生物生长的机制仍然难以捉摸。PI Danna发现MTI导致叶质外体中氨基酸（AAs）浓度的变化，从而改变细菌的生长。PI的研究重点是了解AA转运蛋白（AAT）如何改变限制拟南芥生长的AA浓度。这种反应的一部分是由水杨酸（SA）介导的AAT转录调控协调的。PI假设：1）AAT改变MTI期间叶质外质中AA的浓度，和2）SA协调MTI期间AAT的表达和/或活性。拟进行的实验旨在：1）对导致MTI的AAT进行生物化学和时空表征; 2）研究SA在AAT调节中的作用; 3）评估AAT在调节P. dogingae生长中的作用。PI的长期研究目标是了解为植物提供持久抵抗感染的机制。PI的长期教育目标是通过提供前沿研究培训和促进与职前科学教师的长期合作来改善K-12 STEM教育。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Plants are remarkably resilient organisms that perceive and adaptively respond to challenges, including a broad range of microbes that constantly attempt to use the resources they hold. Understanding how plants achieve long-lasting and broad-range resistance to microbial infection promises to reveal new ways to enhance resistance to microbial disease in crops as well as in ecologically important plant species, a critical challenge in view of the projected 9 billion people that will need food and healthy habitats by the year 2050. The current research aims to understand how plants respond to microbial invaders to restrict infections. Bacterial microbes that multiply in the interstitial space of the leaf obtain all the metabolites and nutrients that they need from their plant hosts. Thus, understanding how plants regulate the composition of the leaf interstitial space will allow for a broader understanding – and potential discovery – of way that plants resist infection. In addition, the research proposed will provide K-12 teachers-in-training with research experience, thereby fostering long-term research collaborations to extend from the University to Virginia to area public schools. Through this, the research presented will expose hundreds of high-school students to inquiry-based, open-ended experimentation that promotes high-order thinking skills. Although a small number of well-adapted microbial species are able to infect target plant species and cause disease, most plants are resistant to most pathogens. This broad-spectrum resistance is in part attributed to the perception of Microbe-Associated Molecular Patterns (MAMPs) and the subsequent elicitation of MAMP-Triggered Immunity (MTI) that suppresses microbial growth. While the MAMP-activated plant signaling programs are increasingly well understood, the mechanisms by which plants restrict microbial growth remain elusive. PI Danna discovered that MTI leads to changes in the concentrations of amino acids (AAs) in the leaf apoplast that alter bacterial growth. The PI’s research focuses on understanding how AAs transporters (AATs) modify AA concentrations that restrict of P. syringae’s growth in Arabidopsis. Part of this response is coordinated by salicylic acid (SA) mediated transcriptional regulation of AATs. The PI hypothesizes that: 1) AATs alter the concentration of AAs in the leaf apoplasm during MTI, and 2) SA coordinates AATs expression and/or activity during MTI. The proposed experiments aim to: 1) Biochemically and spatio-temporally characterize the AATs that contribute to MTI; 2) Investigate the role of SA in the regulation of AATs; 3) Assess the role of AATs in modulating P. syringae’s growth. The PI’s long-term research goal is to understand the mechanisms that provide plants with long lasting resistance to infections. The PI’s long-term educational goal is to improve K-12 STEM education through providing cutting-edge research training and fostering long-term collaborations with pre-service science teachers.This 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.