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I am a plant molecular biologist fascinated by cell-cell signaling and species interactions.

After graduating from the University of Tübingen (Germany) with a degree in Biology, I obtained my PhD from the University of Zurich (Switzerland). I studied cell-cell communication mechanisms between male and female gametophytes in the plant genus Arabidopsis. This spiked my interest in intercellular communication, and I moved on to conduct my postdoctoral research with Maria Harrison at the Boyce Thompson Institute/Cornell (Ithaca, NY). There I started to study another aspect of cellular communication: peptide signaling in the context of arbuscular mycorrhizal symbiosis, a research area that we continue to pursue in the PlantMycoLab.

In my free time, I enjoy traveling, the outdoors, food, and … also plants.

Sagar is a PhD student in the Biological Science program at the University of California, San Diego (UCSD).

Outside of the lab, Sagar enjoys soccer, food, gardening, and hiking (if not sleeping).

Siyi Du is a first-year Molecular and Cell Biology major at the UCSD. She joined the Mueller Lab in Spring 2025 as a student trainee and is currently learning core lab techniques while exploring her interest in molecular biology. She hopes to get involved in research projects in the future to deepen her understanding of gene regulation and cellular mechanisms. In her free time, Siyi enjoys playing badminton and discovering new cafes around San Diego.

Mikayla Kappes received her BA degree in Biology and Spanish from Williams College. While at Williams, she worked as a student researcher studying eco-evolutionary dynamics through Trinidadian guppies, and she did a thesis documenting pollination network interactions in New England. Before returning for her final year of undergrad, Kappes worked in horticulture developing Sonoran Desert gardens in Baja California Sur. While in Baja, she fell in love with working with plants. Kappes began at Salk joining the Busch lab in the fall of ’22 as part of the greenhouse phenotyping team working with all HPI’s crops of interest. In the spring of ‘24, Kappes joined the Mueller lab where she is super excited to dive into studying the molecular mechanisms behind arbuscular mycorrhiza symbiosis. In her free time, Mikayla loves exploring new ways to be active and outside, spending time with her family, friends, and dogs, playing soccer, studying languages, beach time, and all things music related (especially dancing and singing)!

Fabrizio Malatesta is a biology major specializing in bioinformatics at the University of California, San Diego (UCSD). He developed a passion for biological research while working as a research assistant at Weill Cornell Medicine, where he conducted experiments on mitochondrial myopathies in mice. This experience deepened his interest in biology and lab work, motivating him to further explore scientific research. Fabrizio joined the Mueller lab in fall ’24, excited to study the molecular mechanisms behind arbuscular mycorrhiza (AM) symbiosis.

Alex Mueller is a bioinformatics undergraduate at UCSD. Prior to joining the Mueller lab in February 2025, as part of the Phage Genomics Research Initiative, he helped conduct research on nucleus-forming jumbo phage, analyzing how particular phage, upon infecting their bacterial host, develop complex nucleus-like structures to encapsulate their genetic material. In February 2024, Alex, alongside two others, also founded Mycology Club @ UC San Diego and currently serves as its president. Alex is passionate about mycology and is excited to learn and research how different species of arbuscular mycorrhizal fungi (AMF) interact, when colonizing the same host. In his spare time, he enjoys hiking, baking, and growing gourmet mushrooms.

Patricio Ordonez-Acosta (Pato), is a first-year bioengineering student at UC San Diego from Texas and Mexico. Pato’s interest in biological research developed while taking the International Baccalaureate Biology course, where he conducted an in-depth study on microbial resistance, where he studied how light wavelengths affect E. coli survival under Azithromycin exposure. Pato further his research skills through the Harvard Stan-X Animal Transgenesis program, where he worked with Stanford Medicine professors Dr. Seung K. Kim and Dr. Lutz Kochel. There, he utilized CRISPR-Cas9 to modify Drosophila melanogaster, replacing dysfunctional gene sequences with functional bacterial genes. His work contributed to establishing a stable stock of 50 vials for the Indiana University Bloomington’s Drosophila Stock Center and supported ongoing research exploring the replacement of dysfunctional gene sequencing with bacterial genes’ medical applications, currently under review for publication. Pato joined the Mueller lab in winter 2025, excited to study the genetic influences on arbuscular mycorrhizal symbiosis.

Outside the lab, Pato enjoys spending time with his friends, working out, enjoys soccer and Formula 1, traveling, attending concerts, building engineering projects, and represents the USCD Sailing Team.

I am Athira and I joined the Mueller lab as a postdoctoral fellow in October 2024. My research interest and background are in beneficial plant-microbe interactions and symbiosis. I obtained my Ph.D. in Plant Sciences in August 2024 from South Dakota State University, Brookings, USA. My dissertation was on Symbiotic Nitrogen Fixation in soybean, wherein I worked towards understanding the molecular pathways in legume hosts associated with competitive root colonization by different nitrogen-fixing bacterial strains (rhizobia) and symbiotic partner sanctions. At the Mueller lab, I am working on understanding the molecular mechanisms of symbiont preference during Arbuscular Mycorrhizal (AM) symbiosis using Medicago truncatula as a model. I obtained my bachelor’s degree in microbiology and genetics from Osmania University, India, and master’s degree in plant biology and biotechnology from the University of Hyderabad, India. My master’s research was also in the area of plant-microbe interaction in legumes, where I worked on identifying plant resistance in different pea germplasm lines to a fungal pathogen (powdery mildew causing Erysiphe pisi). Before obtaining my doctorate, I also worked as a research assistant for a year at the Repository of Tomato Genomics Resources (RTGR), University of Hyderabad. In my free time, I like to explore new places, take walks, read novels, and watch movies or series. I am also passionate about music and singing.