(2gr) Cracking the Code: Engineering Extracellular RNA and Nanoparticle Trafficking to Control Host-Microbe Interactions

Research Interests: Extracellular trafficking of RNA and other molecules between cells or organisms is essential for the ability of plants to determine whether to mount an immune response or engage in beneficial relationships with microbes. These signals coordinate growth and development, plant immunity, and stress response, so they are an attractive target for engineering efforts to improve food security in a changing climate and enhance disease resistance. In some plant-pathogen interactions, this cross-kingdom communication is facilitated through extracellular vesicles, which are naturally occurring nanoparticles, and has led to interest in using these vesicles and other nanoparticles as biomarkers and RNA delivery agents. However, major questions remain regarding the exact mechanisms of extracellular RNA trafficking and the selectivity and functionality of these molecular signals, particularly in beneficial plant-microbial interactions.

Research Vision: The vision of the Chen Lab is to investigate and exploit the molecular trafficking mechanisms of RNA and nanoparticles in plant-microbe and microbe-microbe interactions to develop technologies that can address major challenges in food security, disease prevention, and soil reclamation. My expertise gained during my graduate and postdoctoral work in genetic engineering, materials science, microbiology, and plant pathology will have prepared me to lead this research program. Primary research directions include:

(1) elucidating intercellular RNA and metabolite trafficking mechanisms in plants under biotic and oxidative stress to identify genetic targets and pathways for engineering improved resiliency

(2) developing beneficial plant-microbe and microbe-microbe interactions for enhanced plant immunity and environmental bioremediation

(3) synthesis and fabrication of novel nanomaterials for disease control and drug delivery

Together, this work promises to reveal new insights into how plants and microbes utilize extracellular vesicles, nanoparticles, or other methods for extracellular trafficking of RNA and other signaling molecules to establish beneficial relationships and combat biotic and abiotic stresses with immediate applications for agriculture. These findings can also be translated to host-microbial interactions in human health to inform the development of next-generation therapeutics.

Postdoctoral Research: As a postdoctoral fellow at the University of California, Riverside with Dr. Hailing Jin, I investigate the mechanisms of cross-kingdom RNA interference and trafficking in plant-fungal interactions to develop new crop protection strategies. Using confocal and electron microscopy, micrografting, and classical biochemistry and genetic techniques, I examine the role of extracellular vesicles in facilitating bidirectional RNA trafficking in model plant-pathogen systems like the Arabidopsis thaliana-Botrytis cinerea interaction. From these insights, I identify new gene targets for RNAi-based fungal control and develop design paradigms for new nanomaterials for anti-fungal RNA delivery that include engineering naturally derived nanovesicles from fruit juices and bacterial-based systems for enhanced and sustained disease control.

Doctoral Research: As an NSF Graduate Research Fellow with Dr. Lydia Contreras and Dr. Benjamin Keitz at the University of Texas at Austin, my research centered on engineering oxidative stress response mechanisms in the nonmodel, polyextremophilic bacterium, Deinococcus radiodurans, for materials science applications. Nanoparticle biosynthesis is an environmentally friendly alternative to traditional chemical synthesis but remains hampered by a limited mechanistic understanding and lack of robust microbial chasses. To address these challenges, I investigated the role of regulatory small RNAs in metal nanoparticle biosynthesis by D. radiodurans and developed a biosynthetic platform in which modulating small RNA expression could be used to tune the antibacterial and catalytic activity of the produced silver nanoparticles, demonstrating genetic control over desirable material properties. Given the conserved nature of small RNAs in gene regulation, this work provides (1) new knowledge into the transcriptional regulation of redox reactions and oxidative stress response in bacteria and (2) a framework for engineering RNA-dependent signaling and processes to control phenotypes of interest in microbes.

Teaching Interests: Inspired by my significant experience in teaching, I am excited to continue educating and mentoring as a faculty member. I have taught a diverse array of courses including process fundamentals/mass balances, introduction to chemical engineering, and thermodynamics, and as such am excited to teach any of the core chemical engineering classes. During my PhD, I completed a Graduate Certification in Engineering Education from the Cockrell School of Engineering at UT Austin. This certification included coursework on effective and inclusive teaching methods in STEM, curriculum design, and a teaching practicum in undergraduate Thermodynamics where I created course materials and taught several full lectures. I would also be interested in developing 2 graduate-level special topics courses. The first course I envision would be an interdisciplinary introductory course on recent innovations in agriculture and food engineering for upper-level undergraduates and graduate students to highlight the growing role of chemical engineers in addressing agronomical challenges. For the second class, I would be excited to leverage my research interests and expertise to lead a graduate seminar on bionanotechnology and extracellular communication in the context of the plant microbiome.

Mentorship and DEI: Outside of research and teaching, I am a strong advocate for improving diversity and inclusion in STEM. My own journey in STEM has been aided by programs focused on introducing historically underrepresented minorities to careers in STEM and great mentorship throughout my academic career. I have nearly a decade of experience as a mentor and role model in programs geared towards the recruitment and retention of historically underrepresented, first-generation, and low-income students in STEM and academia. These include OSU’s Translating Engineering to K-8 program with the KIPP school system, UT Austin’s annual Girl Day, and UC Riverside’s First-Generation Mentorship Program. I have also been a research mentor for many high schoolers, undergraduates, and graduate students in the Contreras and Jin labs, including chemical engineers, biochemists, and plant biologists. As President of the Riverside Postdoctoral Association, I led the planning and execution of several initiatives focused on creating inclusive and diverse environments. These include the creation and distribution of a resource handbook for postdocs, the 1^st annual UC Riverside Postdoctoral Excellence Awards to acknowledge the contributions of postdocs to research, teaching, and the community, and career development and networking opportunities. I am also actively spearheading the establishment of a mentorship series with the UC Riverside Graduate Division and Riverside Underground Scholars to provide formal training in mentoring for postdocs and opportunities to mentor senior graduate students and undergraduates on their next career steps. As an independent investigator, I will seek to implement similar initiatives in my department and university and will continue to advocate for DEI in STEM as an educator and mentor.