Howard S. Judelson was born in New York City. He received a B.S. in biochemistry from Cornell University in 1980 and a Ph.D. in molecular biology from the University of Wisconsin in 1985. His interest in plant pathology began in high school and continued at Cornell. Judelson became a postdoctoral fellow studying lettuce downy mildew at the University of California-Davis. Later, Judelson was appointed to a research faculty position at UC Davis and began working with Phytophthora infestans, the cause of potato late blight. He moved in 1994 to the Department of Plant Pathology, University of California-Riverside, where he is now a Professor.
Judelson's previous honors include the APS Ruth Allen Award in 2004 and Fellow of the American Association for the Advancement of Science in 2016. Judelson is recognized for his contributions towards understanding the basic biology and evolution of oomycete plant pathogens. He established the first techniques for manipulating genes in P. infestans and relatives, created genome resources, and studied cellular pathways involved in pathogenesis. Overall, Judelson made significant contribution and achievements in original research, teaching, and professional and public service.
Judelson's early contributions involved designing vectors and procedures for DNA-mediated transformation, a critical tool for studying pathogen biology. Protocols first developed for P. infestans were later extended by his laboratory and others to additional species of Phytophthora and Pythium. Further enhancements included methods for testing gene function by RNA silencing, and families of vectors for labeling proteins with fluorescent tags to investigate their function. So far, vectors developed in the Judelson laboratory have been distributed to over 140 laboratories in 31 countries and have been widely used for genetic manipulation of Phytophthora and Pythium. In addition, Judelson has trained many visiting scientists in transformation technology.
Another major contribution of Judelson to oomycete research is the development genome databases and allied resources. He and collaborators released a large-scale expressed sequence tag database for P. infestans, the first for any oomycete, and microarray data that described the expression of most genes at different stages of the life cycle. He was a principal member of a consortium that sequenced and annotated the genome of P. infestans. Later, he generated and released extensive RNAseq data that describe the expression of genes during pre-infection stages and plant colonization, which provided insight into mechanisms of pathogenesis.
Using genomic, genetic, biochemical, and cell biology approaches, much insight into P. infestans biology has been revealed from his research program. For example, studies of nitrate assimilation showed how that metabolic pathway contributes to pathogenesis in a host organ-specific manner. Other research addressed the genetic basis of resistance to metalaxyl, a widely used fungicide. Judelson's group also identified cellular regulators and signaling pathways that regulate spore formation and germination. For example, the Cdc14 phosphatase was shown to be a key a regulator of sporulation. Studies of transcription factors identified key regulators of sporulation, appressorium development, and responses to oxidative stress. Comparative studies with other oomycetes such as Hyaloperonospora and Pythium yielded insight into the evolution of biotrophic, hemibiotrophic, and necrotrophic pathogens, including how metabolic pathways have evolved to support the different lifestyles.
Judelson’s work has also influenced the applied aspects of potato late blight management. Through technology transfer and consulting, he has helped private sector scientists identify targets for fungicides. Judelson also organized a multidisciplinary team focused on improving the management of late blight. This led to a large (>$9M) five-year project funded by USDA-NIFA. As the Principal Investigator on this project, Judelson coordinated 26 researchers and extension personnel from 20 institutions. This project established a network of extension personnel focused on late blight, generated instructional materials for growers, provided nationwide monitoring of pathogen genotypes and phenotypes, improved strategies for timing fungicide applications, developed new diagnostic assays and host cultivars with improved resistance to P. infestans, and tested several plant-based technologies for resistance.
Judelson has a reputation of excellence that is recognized nationally and internationally. He has a publication record with 92 technical papers (with 2487 non-self citations and an h-index of 30). His research has been supported by numerous competitive grants, with 30 and 23 years of continuous support from USDA and NSF, respectively. He has collaborated with researchers all over the world. He has also consulted for nine agribusiness firms in the United States and Europe, and served on 24 grant review panels for state and federal government agencies. Judelson has evaluated 231 papers over the past 13 years including APS journals.
Judelson's professional service contributions include being an associate editor of Molecular Plant-Microbe Interactions (3 years), senior editor for Molecular Plant Pathology (6 years) and Plant Cell Reports (19 years). He was a member of the Genetics Committee of APS, and a session moderator at APS-sponsored meetings. He also organized international conferences on oomycete genetics and on late blight.
Judelson's career includes significant service as a mentor of young scientists. He has supervised the research of 11 Ph.D. students, 15 postdoctoral scholars, and 24 undergraduates. Many of his former students are now practicing professionals in plant pathology as researchers, instructors, or managers of diagnostic clinics. Judelson has also directed three summer research programs for undergraduates with a focus on plant pathogens, providing experiences to 172 students over the past ten years. He is a dedicated and popular instructor in both undergraduate and graduate courses in plant pathology and related fields, served as faculty advisor in the plant pathology graduate program, and directs an undergraduate major (Cell, Molecular and Developmental Biology). His other service contributions to UC-Riverside are extensive and include membership on numerous committees, including 14 years as chair of the Institutional Biosafety Committee.
In summary, over his professional life of more than three decades Judelson has made significant fundamental contributions to studies of oomycete plant pathogens, and has advanced the discipline and mission of APS.