This award recognizes outstanding contributions to regulatory plant pathology, crop security, and trade enhancement efforts by APS members.
Gitta Coaker is the John & Joan Fiddyment Endowed Chair and professor in the Department of Plant Pathology at the University of California, Davis. Coaker received her B.S. degree (1998) in ecology and evolutionary biology from the University of Arizona, and her Ph.D. degree (2003) from The Ohio State University. Coaker was a postdoctoral fellow in the Department of Plant and Microbial Biology, University of California, Berkeley. She was appointed to assistant professor at UC Davis in 2007 and has been a full professor since 2017.
For the past 18 years, Coaker and her large group of collaborators have tackled one of the most intriguing challenges for plant pathologists, that is, how plant interactions with microbial pathogens result in resistance or disease. Coaker has approached this challenge from both the plant and pathogen sides by integrating physiological, molecular, genomic, and genetic
approaches. She studies three different plant-pathogen systems: Arabidopsis/Tomato Pseudomonas syringae, tomato-Clavibacter michiganensis, and citrus-Candidatus Liberibacter asciaticus. Her long-term goal is to obtain a fundamental understanding of plant-pathogen interactions with translational potential for disease control. In her studies of Arabidopsis, Coaker used the intracellular nucleotide-binding domain leucine-rich repeat (NLR) proteins RPM1 and RPS2 to investigate pathogen effector recognition. Her team demonstrated that the RPM1 immune receptor indirectly recognizes Pseudomonas effectors through effector-induced phosphorylation of a conserved host protein, RIN4. She also investigates how protein kinases regulate plant responses to pathogens at multiple levels.
Although extracellular pattern recognition receptors (PRRs) and NLRs are structurally distinct and recognize different pathogen components, they share significant overlap in downstream signaling. In collaboration with Cyril Zipfel (University of Zurich) and Ken Shirasu (RINKEN, Japan), Coaker discovered that key immune signaling nodes are regulated by phosphorylation, but the kinases involved can differ depending on receptor type. She has also identified lectin receptor-like kinases and cysteine-rich receptor-like kinases (CRKs) that are important for plant defense. Collectively, these findings highlight overlap in PRR- and NLR-mediated responses.
Coaker and collaborators are also translating mechanistic findings from model systems into other species, including citrus. Citrus is a member of the Rutaceae family, and commercial sweet
orange varieties are susceptible to multiple bacterial diseases, including huanglongbing (HLB), a devastating vector-borne disease associated with the bacterial pathogen Candidatus Liberibacter asciaticus. Coaker is investigating the diversity of citrus PRR responses. She leads a large multi-institutional effort between UC Davis, UC Riverside, University of Florida, USDA, and Texas A&M. She has developed immune assays to survey PRR responses in diverse citrus genotypes and is stacking receptors for more robust disease resistance. She is also studying how these important pathogens manipulate their host or vector to facilitate pathogen colonization, movement, or spread. For example, she is investigating the role of Pseudomonas effectors in Arabidopsis and tomato, the role of Clavibacter effectors in tomato, as well as investigating the plant targets of Liberibacter effectors.
Coaker’s research continues to positively affect the field of molecular plant pathology. Her research group has published 66 peer-reviewed scientific publications since her appointment as professor at UC Davis, many in high-level journals, including Cell Host and Microbe, The Plant Cell, Nature Communications, PNAS, and the Annual Review of Phytopathology. Since appointment at UC Davis, Coaker has given over 120 invited talks in 14 different countries. Coaker continues to be highly creative and successful. She serves as the PI on a $4 million-dollar USDA grant focused on the devastating citrus disease, HLB. Her research on kinase-mediated signaling and effector biology has been supported by 11 years of continuous funding from the National Institutes of Health and is currently supported by an NIH R35 Outstanding Investigator’s Award, as well as a joint NSF-USDA grant.
Coaker’s contributions to research and mentorship have been widely recognized. She received the 2020 Graduate Student Mentoring Award (University of California Davis), a 2020 NIH MIRA R35 Outstanding Investigator Award, the 2013 Chancellor's Fellow for Research Excellence (UC Davis), and a 2011 NSF CAREER Award. She serves on several editorial boards, including as senior editor for Molecular Plant Pathology since 2017. She also serves as an editorial board member of Molecular Plant Pathology and as an associate editor for PLoS Genetics. In conclusion, Gitta Coaker has demonstrated excellence and leadership in research that significantly advances the understanding of molecular plant-pathogen interactions.