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

About This Grant

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.