Savithramma Dinesh-Kumar was born in Bhadravathi, India, and he received his BSc and MSc in genetics from the University of Agricultural Sciences in Bangaluru, India. Following a brief period as an instructor, he moved to the United States and received his PhD in molecular, cellular, and developmental biology from Iowa State University. He received a Life Science Research Fellowship, which funded his post-doctoral work at the USDA–ARS Plant Gene Expression Center (PGEC) and the University of California, Berkeley. In 1999, he accepted a faculty position in the Department of Molecular, Cellular, and Developmental Biology at Yale University; he advanced to associate professor in 2004. In 2010, he moved to the Department of Plant Biology at the University of California, Davis, where he is now a professor and the department chair and a professor in The Genome Center.
Dinesh-Kumar is internationally recognized for his significant contributions to understanding the molecular basis of plant immune responses to pathogen infections. His PhD dissertation research in Dr. Allen Miller's laboratory was a harbinger of the seminal contributions that have followed. Dinesh-Kumar revealed the leaky-scanning and translational read-through mechanisms employed by barley yellow dwarf virus (BYDV) to produce three different proteins under the direction of a single subgenomic RNA. He also constructed the first successful BYDV infectious clone. Subsequently, he pursued post-doctoral research in Dr. Barbara Baker's laboratory at PGEC–University of California, Berkeley. There, he was involved in cloning the first virus resistance gene, N, that confers resistance to tobacco mosaic virus (TMV). Dinesh-Kumar's insightful analysis identified the amino end of the N protein as resembling Drosophila Toll and mammalian Interleukin-1 receptor, now referred to as the “Toll-Interleukin-1 receptor (TIR) homology domain." This was the first TIR domain identified in plants and was identified long before mammalian Toll-like receptors were identified. The TIR receptor domain containing nucleotide-binding leucine-rich repeat (NLR) class immune receptors are now recognized as universal receptors that function in plant and animal immunity. In addition to elucidating the roles of various N protein domains, Dinesh-Kumar's work described the role of alternative splicing in N function—a phenomenon documented only later in other systems. Most of what we know about N can be attributed to his work.
Dinesh-Kumar's research has greatly advanced our understanding of connections to plant defense of both chloroplast function and autophagy and opened new doors in the study of plant immunity. During TMV infection, TMV accumulates in a ring that is a few cells thick, outside the necrotic area in NN plants. Therefore, it is not the necrosis per se that constrains TMV from systemically infecting the plant but some aspect of the ring of living tissue. Dinesh-Kumar and his colleagues solved the mystery of this constraint with their discovery that autophagy, in which cytoplasmic entities are transported to the vacuole for destruction, occurs in TMV-infected leaves and is essential to limiting expansion of the necrotic area and constraining the infection. Dinesh-Kumar and his colleagues also provided the lead in developing our understanding of the role of chloroplasts in pathogen recognition and defense. They showed that stromules, which are tubular extensions of chloroplasts and other plastids, develop during plant recognition of pathogen invasion. In 2015, his group published a seminal cover-page article in Developmental Cell that for the first time demonstrated a function for stromules in immunity. This paper was listed in the “2015 Plant Science Round-Up" as one of the year's groundbreaking publications. Recently, Dinesh-Kumar's group demonstrated that the stromules assist chloroplasts in congregating with the nucleus, mediating transfer of defense-related molecules to the nucleus and the subsequent development of a hypersensitive response. This novel stromule-driven chloroplast movement toward the nucleus during immunity is facilitated by the cytoskeleton. These advances opened two new subfields of plant biology, chloroplast–nucleus communication and autophagy, as processes central to plant response to pathogens.
Dinesh-Kumar also developed important tools for gene function studies, including the tobacco rattle virus-based, virus-induced gene silencing system. This system provides experimental transient control over the expression of a specific gene and has demonstrated utility in more than 25 plant species. More recently, he and collaborators used this viral system to deliver gRNA for CRISPR/Cas9-mediated genome editing. Dinesh-Kumar and associates pioneered microarrays built with Arabidopsis proteins produced in a plant system, allowing for the first time large-scale assessment of plant and plant pathogen protein–protein interactions. His laboratory has assisted many research groups in identifying important regulators of immunity using protein microarrays. In addition to advancing his own research work, these tools have benefited the scientific community worldwide.
Although the principal focus of virus–plant interactions is resistance, in fact, there are host components that favor virus success. Dinesh-Kumar's research provided the first evidence for the role for P58IPK as a common host factor in plant and animal viral pathogenesis. P58IPK, an inhibitor of double-stranded RNA-activated protein kinase, interacts with specific virus proteins, suggesting a fundamental role for P58IPK in the virus infection cycle. More recently, Dinesh-Kumar's laboratory described a fluorescent protein-based method for direct visualization of bacterial effectors delivered from the type III secretion system into plant cells. Recently, his group determined the structure of the receptor-like cytoplasmic kinase BIK1, which functions as a key signal integrator of plasma membrane-localized leucine-rich repeat receptor kinases that modulate growth and immune response signaling in plants. The BIK1 structure-guided functional analyses uncovered an unknown role for jasmonic acid hormone in bacterial resistance.
Dinesh-Kumar's research discoveries have led to the creation of many new paradigms and raised and answered many crucial questions in the field of plant immunity. His publication record is exceptional, with more than 110 research papers and reviews (most of which are published in high-impact journals) and 11 book chapters; he also holds three patents. His research accomplishments are recognized by a number of awards, including Fellow of the AAAS in 2018; the University of California, Davis Faculty Research Award in 2016; a Junior Faculty Fellowship in 2003; and a Hellman Family Fellowship in 2000. He served as a senior editor of MPMI from 2004 to 2006, as an advisory board member of Plant Journal from 2004 to 2006, and as an editorial board member of Autophagy from 2006 to 2010. He is currently an associate editor of PLoS Pathogens, a senior editor of Phytopathology Research, an editorial board member of Molecular & Cellular Proteomics, and an academic editor of Peer J. He is a member of the American Society of Plant Biology Minority Affairs Committee. Dinesh-Kumar has trained numerous undergraduate and graduate students, post-doctoral fellows, and international and national visitors in his laboratory.
