Dr. Ing-Ming Lee was born February 26, 1943 in Taiwan. He obtained his B.S. degree in plant pathology from National Taiwan University in 1965. In 1966, Dr. Lee joined the Taiwan Citrus Protection Research Center, where he investigated major fungal diseases of citrus. In 1971 he came to the United States and began graduate studies at the University of California, Riverside. He received his M.S. degree in 1973 and his Ph.D. degree in 1977. After his postdoctoral positions with the USDA-Agricultural Research Service (ARS), Rutgers University, and the University of Maryland, Dr. Lee joined the Molecular Plant Pathology Laboratory, USDA-ARS (Beltsville, Maryland), as research plant pathologist in 1987.
Dr. Lee began his innovative research career as graduate student at the University of California, Riverside, where he pioneered research on citrus stubborn disease. In 1973, after more than 20 years of unsuccessful searches by entomologists looking for the vector of citrus stubborn disease pathogen (Spiroplasma citri), his novel approach, involving direct cultivation of the pathogen from insects, led to his discovery of the first known natural vector (Circulifer tenellus). This discovery was recognized worldwide as a major breakthrough for citrus stubborn disease research and it opened the way for subsequent work that proved conclusively that a wall-less bacterium caused a plant disease.
Dr. Lee is recognized internationally for important contributions to understanding cell wall-less plant-pathogenic bacteria of Mollicutes (spiroplasmas and phytoplasmas) and the diseases they cause. In early work as a postdoctoral researcher, he led development of new media including the first serum-free and chemically defined media, for cultivation of S. citri, S. kunkelii, and other spiroplasmas. Based on DNA homology studies and serological relationships, Dr. Lee with his colleagues proposed the first taxonomic classification of spiroplasmas. The new taxonomic criteria were adopted internationally and new Spiroplasma species named accordingly.
Dr. Lee is best known for his pioneering studies on molecular detection, identification, and classification of phytoplasmas. In the past decade, he and his colleagues devised new methods and reliable molecular tools (cloned DNA probes and monoclonal antibodies) for phytoplasma detection. This made it possible to study the genetic interrelatedness among diverse phytoplasmas. Dr. Lee and colleagues in 1992 proposed several distinct phytoplasma groups (genomic clusters) and constructed the first genotype-based differentiation of phytoplasma strains. These new molecularbased tools greatly advanced phytoplasma diagnostics and largely replaced traditional approaches based on biological properties, such as symptomatology, host range, and vector relationships.
In 1993, Dr. Lee and colleagues constructed the first comprehensive phytoplasma classification system, based on restriction fragment length polymorphism (RFLP) analysis of 16S rDNA. This novel system provided for the first time a rapid and accurate means for differentiation and identification of a broad array of phytoplasmas. Dr. Lee led a team that further expanded the classification system in 1998 and again in 2000 to include 15 major phytoplasma groups and over 40 subgroups, providing the most comprehensive phytoplasma classification system available. This approach changed the direction of phytoplasma research. As a result, the phytoplasma research field has dramatically expanded in the last 10 years. It has been recognized by international peers as a major breakthrough for classification of phytoplasmas and has been adopted by scientists worldwide. The scheme is currently used by the National Center for Biotechnology Information (NCBI)/GenBank for classification of phytoplasmas.
Dr. Lee and colleagues also developed ultrasensitive nested PCR assays, enabling detection of low titers of phytoplasmas associated with woody plants and detection of multiple phytoplasmas (mixed infections) in the same plant. As a result, Dr. Lee and his collaborators solved etiologies of many emerging phytoplasmal diseases. Using this framework, Dr. Lee and colleagues gained new insights into phytoplasma ecology and genomic diversity and devised a model of phytoplasma evolution driven by ecological constraints, a model supported by his recent study of an aster yellows disease epidemic in Texas.
Dr. Lee’s accomplishments also include the discovery, in 1997, that a phytoplasma causes desirable free-branching in commercial poinsettia cultivars. This was the first example of using molecular means to fulfill (a modified) Koch’s postulates to prove pathogenicity of any phytoplasma, and the first definitive demonstration of a commercially beneficial phytoplasma.
In 1994, Dr. Lee led the first global phylogenetic analysis (graduate study of Ph.D. student Dawn E. Gundersen, advised by Dr. Lee); this accomplishment placed phytoplasmas definitively among members of class Mollicutes and revealed that phytoplasmas form a large discrete monophyletic clade. Significantly, all subclades corresponded to 16S rDNA RFLP groups previously delineated by Lee’s team. Lee and his team proposed that each phylogenetic subclade represented at least one Phytoplasma species. This study formed the basis for delineating new genus and species level taxa, and led to establishment of formal phytoplasma taxonomy in which over 20 ‘Candidatus Phytoplasma species’ have been proposed.
While researching phytoplasmas, Dr. Lee extended his research to include walled, bacterial pathogens. He and colleagues developed sensitive and specific PCR-based assays enabling detection of potato ring rot bacterium Clavibacter michiganensis subsp. sepedonicus and brown rot bacterium Ralstonia solanacearum biovar 2/race 3 in symptomless seed potatoes, an essential step to meet zero tolerance for import/export of seed potatoes. His assay for R. solanacearum biovar 2/race 3 (currently under U.S. quarantine) was adopted by APHIS to verify identity of a new strain that appeared to be responsible for an outbreak of geranium wilt disease in the United States.
Dr. Lee has demonstrated a career-long dedication to research on plant-pathogenic Mollicutes. His achievements have established him as an authority and leader in the field of plant pathology and phytoplasma research. During the past decade, he has initiated successful collaborative studies on phytoplasmas nationally and internationally and has trained many U.S. and international scientists, including two Ph.D. students. Dr. Lee has been invited as a U.S. and international expert and consultant and has delivered numerous invitational seminars in national and international meetings. Dr. Lee has been a review panel member of USAID, has participated in APS as amember of APS Bacteriology Committee, chaired sessions at APS Annual Meetings, and served as an associate editor for Plant Disease.
