Rice blast is a compelling model system for studying host–parasite interactions due to its socioeconomic impact and amenability to molecular genetic analysis coupled with the availability of both the rice (in 2002) and Magnaporthe genomic sequences (in 2005). In an attempt to understand the molecular mechanisms of rice blast disease, Lee’s group has undertaken a number of genome-wide studies and was early pioneers of both forward and reverse genetics approaches. At the same time, he also recognized the potential of computational biology to gain insight into fungal pathogenesis.
Dr. Lee’s impacts on understanding the basis of fungal pathogenesis reach back more than 20 years. An early and insightful significant contribution using a reverse genetics approach was the identification and characterization of genes involved in signal transduction pathways leading to appressorium formation in the rice blast fungus. His seminal work led to the discovery that cAMP acts as a crucial second messenger in stimulating the infection process. Subsequent studies included deciphering of other signaling pathways including calcium- and MAP-kinase dependent pathways. These series of elegant studies provided new insights into molecular mechanisms of infection by the rice blast fungus and moreover also directed new research areas in other plant pathogenic fungi.
Using landmark forward genetics screens, Dr. Lee’s group has carried out a large-scale insertional mutagenesis of the M. oryzae strain KJ201 via Agrobacterium tumefaciens-mediated transformation (ATMT), generating over 21,000 mutants. His group also developed a high throughput phenotype screening system that enables rapid and robust assay of mutant phenotypes. Using this novel functional genomics and phenomics platform, 201 new pathogenicity genes were identified in rice blast fungus, the largest unbiased collection of pathogenicity genes yet discovered for a single species. More recently, Dr. Lee’s group developed activation tagging system via ATMT and generated over 5,000 mutants. Those mutants are stored and maintained in the Center for Fungal Genetic Resources instituted under the support of the National Research Foundation of Korea.
Transcription factors are key drivers in biology and typically act downstream of signaling pathways. In order to gain new insight into their function, Dr. Lee’s group systemically characterized hundreds of transcription factors genes in the genome of M. oryzae. This tour de-force, not only included genome-wide bioinformatics analysis and expression profiling, but also functional characterization. This work has opened the door for many downstream studies by the research community.
DNA methylation is an important epigenetic modification that regulates development of eukaryotes including plants and mammals. To understand the roles of DNA methylation in fungal development and pathogenicity, Dr. Lee’s group combined genetic manipulations and profiling genome-wide methylation patterns at single-nucleotide resolution during infection-related morphogenesis in M. oryzae. This comprehensive research provides new platform for studying epigenetic regulation of fungal pathogenesis in plant pathology community.
In addition to endeavors to decipher the molecular understanding of rice blast disease, Lee’s group has actively participated in a number of major genome sequencing projects on both fungi and host plants. He has also built a cyber-infrastructure (bioinformatics portal system) for storage of vast heterogeneous data sets he and other colleagues have generated. This portal is of great utility to the scientific community for not only for access to genome data, but it also provides thoroughly analyzed with outstanding documentation of such data in multiple contexts. The database contains numerous curated fungal genomic data sets including transcription factors, peroxidases, cytochrome P450s, cell wall degrading enzymes and secreted proteins. The genome sequence information as well as results from experimental biology is housed in customized and user-friendly databases open to the research community. In 2013, he was awarded the Ruth Allen award for development of cyberinfrastructure for plant pathogens and bioinformatics portal system, Comparative Fungal Genomics Platform.
Dr. Lee has been active in administration at Seoul National University, serving as Director of University Plant Clinic, Department Head and Associate Dean for Research. He organized international plant pathology conferences including 6th International Rice Blast Conference in 2013. He is currently president of the Korean Society of Plant Pathology (KSPP) and President-elect of Asian Association of Societies for Plant Pathology. Dr. Lee’s contribution in the community has been well recognized internationally. He has been invited as a K.P. Chair Professor at Zhejiang University in China (2008-2011) and a Finland Distinguished Professor at University of Helsinki in Finland (2010-2015). In 2016, Dr. Lee was elected as a member of The Korean Academy of Science and Technology.
In summary, Lee’s group has been undertaking comprehensive and integrative approaches for more than 2 decades to understand the complex and subtle nature of fungal pathogenesis, using the technologies at the leading edge of the field. His work on understanding fungal pathogenicity provides not only new insights into the mechanisms and evolution involved in fungus-plant interactions but also the molecular foundation on which efficient and stable crop protection strategies can be built.