Current Personnel


Pam Ronald
Pamela Ronald
I am a professor in the Dept of Plant Pathology and the Genome Center at UC Davis. I have a PhD in Molecular and Physiological Plant Biology from UC Berkeley and was a postdoc at Cornell. I got interested in plant microbe interactions while studying biology at Reed College and later moved to Sweden to study mycorrhizal fungi. I enjoyed living in Sweden/France for three years but am glad to be back in California, where I grew up. When not doing science, I love to spend time hiking in the Sierra Nevada mountains with my friends, family and our dog.
Valley Stewart
I am Professor Emeritus in the Department of Microbiology & Molecular Genetics. I earned a B.A. in biology from the University of Colorado and a Ph.D. in microbiology from the University of Virginia, and completed postdoctoral training at Stanford University. I moved to UC Davis after twelve years on the faculty at Cornell University. My research focused on studying the physiology and genetics of enterobacteria. I have been collaborating with Prof. Ronald since 2016, focusing on Xanthomonas oryzae pv. oryzae. I love to play trumpet with the UC Davis symphony orchestra and concert band, and I also enjoy golfing, reading about politics and history, and spending time with my wife, our daughter and the family dog.

Visiting Faculty

Felipe Ricachenevsky
I am a professor from the Federal University of Rio Grande do Sul in Brazil. My group focus is plant nutrition and ionomics, and the genetics that controls it. Our goal is to enhance the nutrient content of staple grains like rice, and to gain a deeper understanding of the processes that govern the uptake and distribution of nutrients within plants. This will aid in making fertilizer usage more sustainable and cost-effective. During my time at the laboratory, I plan to utilize Kitbase as a tool for both forward and reverse genetic screening. In addition to being a scientist, I am also passionate about teaching. In my free time, I love spending as much time as possible with my daughter and wife, especially if we go on trips; reading books, running, and playing music.


Randy Ruan
I am Professor Ronald’s Lab Manager. I graduated in Yangzhou University in China with a Master and Bachelor in Agronomy and Plant Genetics. I moved to United States in 1994 and joined Ronald lab in Dec 1994. I enjoy working with Pam and the hardworking lab group. Besides working on research and manage Ronald lab I spend most my spare time on gardening. Karen and I have a son Colin and two cats, Big Guy and Calypso.

Assistant Project Scientist

Maria Florencia Ercoli
I am originally from Argentina; I have a Ph.D. in Biological Sciences and a BSc in Biotechnology from the National University of Rosario. During my Ph.D. I studied regulatory networks controlling Arabidopsis root development and discovered my passion for plant genetics and molecular biology. I decided to apply this expertise to a different plant model, a crop, so in 2018 I joined the Laboratory of Prof. Pamela Ronald as a Postdoctoral Scholar. I am currently working as part of a team that, using different approaches, aims to elucidate the molecular mechanisms underlying the ability of small peptides to control plant development and plant-microbe interactions. My passion is to see life through a microscope; therefore, I approached this key research question from a cellular biology perspective, studying the anatomical modifications these hormones are causing in detail. If you want to see fun pictures from our research, you can find me on Twitter (@NeCesiTo1TiemP0).
In my free time, I love spending time with my husband Jean and our dog Gino; we go for hikes, camping, and bike rides. I also love cooking, watercolor painting, and gardening.

Postdoctoral Scholars

Artur Teixeira de Araujo Junior
I am a postdoc in Ronald Laboratory (Department of Plant Pathology – UC Davis). I have a PhD in Cellular and Molecular Biology from the Federal University of Rio Grande do Sul (Brazil) and a masters in Biotechnology from the Federal University of Pelotas (Brazil). I also had the experience of being a Rural Producer and Property manager in a farm for 6 years. This helped me to understand the vision of two very different points of work: developer of new technology and producer/user of these final products. I am responsible for the collection of rice mutants (KitBase) and sorghum mutants. My projects involve bioinformatics, laboratory and greenhouse work. I'm glad to study and learn about the modifications in the DNA and how these mutations can help the society with plants more tolerant to stress, more productive and with greater nutritional value in grains. In my free time, I like to improve my creative side and to do physical activities (hiking, climbing, among others).
Dee Dee Luu
I joined the Ronald lab as a graduate student, graduated with a Ph.D. in Microbiology, and now work as a postdoc. I earned my B.S. at UC Irvine studying poliovirus translation initiation. I then moved on to studying baculoviruses at Cal State Long Beach before I settled at UC Davis. My current research examines the virulence effects of a bacterial peptide that mimics the plant host. In my spare time, I enjoy DIY projects and creating art.
Alyx Shigenaga
I joined the Ronald Lab as a Postdoctoral Researcher in August 2021. I have a PhD in Plant Pathology from Colorado State University and a BSc in Microbiology and Botany from Humboldt State University. During my PhD, I studied the role the plant hormone cytokinin plays in heat-induced disease susceptibility of plants to bacterial pathogens. To learn more about my PhD research, you can see my 3-minute lightning talk here. My current research in the Ronald Lab focuses on further understanding the biological role sulfated plant peptide hormones play in plant-microbe interactions and identifying/characterizing the PSY receptor using various plant systems. Besides doing science, I enjoy spending time with my husband and dog outdoors hiking, kayaking, or swimming. You can follow me on Google Scholar.
Ellen Rim
I am a Life Sciences Research Foundation postdoctoral scholar studying rice immune receptor signaling with the goal of developing crops with greater pathogen resistance. I studied animal systems throughout my undergraduate years at Harvard College and PhD studies at Stanford University focusing on cell signaling in mammalian stem cells. Towards the end of graduate school, I became interested in plants and the role of plant sciences in addressing climate change and food security. In the Ronald Lab, I'm learning a lot about crops and engineering plant immune receptors to expand their pathogen recognition ability. Outside of lab, I enjoy cycling and playing ultimate frisbee.
Peter Lynagh
I went to college hoping to learn about Kenyan coffee, which I love. I earned an agricultural B.S. from University of Maryland where I assisted in researching soils, greenhouse gases and insects. More recently, my UC Davis Plant Biology Ph.D. research improved detection and characterization of genome edits in plants. I developed a plant PCR method that is faster, less expensive, easier, uses less plastic and chemicals, and causes minimal tissue damage. My first postdoctoral position is here in the Ronald Lab. I am analyzing rice root system architectures, and related aspects, for improving carbon sequestration in soil.
Jin CY Liao
I received my PhD in Plant Biology from Iowa State University. My PhD works were trying to understand the complicated molecular mechanisms by which plants regulate in response to dynamic environmental conditions. I particularly focused on the interplay between autophagy and phytohormone brassinosteroid signaling in Arabidopsis. I am currently working on the regulation of plant peptide hormones and their receptors in the Ronald Lab. Besides research, I am also passionate about travel and science communication. I have my own website Jin's LifeRχiv (, and most of my posts are about plant biology. I create funny and cute illustrations/comics that explain the latest plant science research in a way everyone can understand.
Yejin Shim
I joined the Ronald Lab as a postdoctoral researcher in June 2023. I earned my Ph.D. in Crop Science and Biotechnology from Seoul National University in South Korea, following my Bachelor's and Master's degrees from the same institution. During my doctoral studies, my research focused on understanding the genetic and molecular mechanisms controlling flowering time and abiotic stress tolerance in rice. In this laboratory, I am eager to explore the transcriptional regulators of PSY and its multifaceted roles, encompassing plant immunity and developmental processes. In addition to my scientific pursuits, I love to play the violin and tennis.

Visiting Researchers

Kashaf Zafar
I have joined Ronald's Lab as a visiting scholar. I am passionate about learning new things and found it very interesting to gain experience from here. Currently, I am working on understanding the role of plant peptide hormones on root development in rice. I have done PhD in Agricultural Biotechnology from National Institute for Biotechnology and Genetic Engineering, Pakistan. My PhD work was on Establishment of genome engineering for herbicide and bacterial blight resistance in Basmati rice using CRISPR/Cas9. I have mutated the promoter region of SWEET14 gene using non homologous end joining (NHEJ) to develop resistance against bacterial blight. To develop herbicide tolerance, the Acetolactate synthase gene of basmati rice was targeted using homology directed repair (HDR). I have also worked on CRISPR based directed evolution as a visiting researcher at King Abdullah University of science and technology, Saudi Arabia. Other than science related things, I love to spend time with my family, and I also enjoy cooking.

Junior Specialist

Tracy Weitz
I am a recent graduate from UC Davis with a Bachelor's Degree in plant biology. I have a passion for molecular biology and plant-microbe interactions. My previous worked focused on the effects of elevated temperature on human pathogen contamination of lettuce. In my free time, I love to cook, bake, and spend time in nature.
Oscar Garrett
I joined the Ronald Lab as a junior specialist in late summer 2023. I earned my B.S. in Biology at Haverford College in Haverford, PA, but stem initially from rural Northeast Ohio. During my undergraduate studies, I investigated how microbes use small molecule messengers to communicate on a biomolecular level, focusing on interactions between marine phytoplankton, bacteria, and viruses. At the Ronald Lab, I've now shifted my focus to terrestrial plants, studying how rice recognizes and coordinates an immune response to pathogens. I hope to use this knowledge to engineer plants with enhanced pathogen recognition abilities. Outside of the lab, I enjoy cooking, gardening, hiking, and foraging for plants and fungi.
Nguyen Ho
I'm a Computer Science new grad from UC Davis, and I joined Ronald laboratory to help with data computation analysis and managing websites. In my spare time, I like to play and watch soccer. My favorite team is Manchester United (UK).

Graduate Student Researchers

Alexander Howard
I am a graduate student who joined the Ronald Lab in the spring of 2023. I earned a B.S. in Biotechnology at the University of Nevada, Reno and am originally from Boise, Idaho. During my undergraduate I researched how drought stress influences 3'UTR isoform expression in grapevines. I found that 3'UTRs are highly dynamic and may play an important role in regulating transcript stability and translation during droughts. This work sparked an interest in bioinformatics which has remained a constant passion of mine ever since. My main goal at the Ronald Lab is to use bioinformatics and machine learning techniques to optimize the design of more effective immune receptors in plants. Beyond lab work I enjoy cooking and baking for friends, gardening, and outdoor activities like hiking and skiing.

Undergraduate Assistants

Rafael Vasquez-Chan
I am an undergraduate student here at UC Davis pursuing a degree in biotechnology with a focus on plants. I joined the Ronald lab to work with Peter in improving carbon sequestration by rice. I like to spend my free time playing video games, being in nature, and doing dragon boat with UC Davis team.