Neal Stewart, Jr., Ph.D. is a professor of plant sciences, the Ivan Racheff Chair of Excellence in Plant Molecular Genetics at the University of Tennessee Institute of Agriculture (UTIA), and co-director of the Tennessee Plant Research Center. His primary research interest is exploring how genetic engineering can positively impact the environment with focus areas in plant biotechnology, synthetic biology, genomics, and ecology. Dr. Stewart obtained his Ph.D. in biology (plant physiology) from Virginia Tech and was a postdoctoral researcher at the University of Georgia. He served as an assistant, and then associate, professor of biology for seven years at the University of North Carolina at Greensboro before joining UTIA in 2002.
One of Dr. Stewart’s current research focuses is the use of promoters to induce gene expression for desirable traits in plants. While conducting switchgrass genetic engineering research at Oak Ridge National Laboratory’s Bioenergy Science Center, Dr. Stewart discovered a switchgrass promoter that consistently produced a broad range of gene expression. His discovery is notable since there are few plant-based promoters available for genetic engineering, and not many promoters possess very strong gene expression. In addition, this switchgrass promoter does not require an environmental trigger to work (it is “turned on” all the time) and can be successfully inserted into a number of economically important grass crops, like corn, wheat, or sorghum. A patent for Dr. Stewart’s promoter technology was issued in December 2013, and a non-exclusive license agreement was executed by the University of Tennessee Research Foundation (UTRF) in October 2017 with Amfora, Inc., a startup agricultural company based in San Francisco, California.
Dr. Stewart’s interest in promoters extends beyond those used in grass crops to include green tissue promoters, which drive gene expression in a plant’s stems and leaves, and inducible promoters that create fluorescent proteins, allowing a plant to change color. He is using the latter type of promoter to create phytosensors, or plants that can detect changes in their environment, such as infection by a pathogen. Taking this concept a step further, Dr. Stewart is exploring the potential to produce plants that can detect mold, even explosives.
Another area of interest for Dr. Stewart is synthetic biology, which uses biology and computational design tools to synthesize synthetic genes and genomes for plants that confer them with entirely new functions. He and his lab team are currently developing synthetic chloroplast genomes, called “synplastomes,” which are expected to produce extremely high expression of desired genes and improved consistency of trait expression. This work has the potential to significantly advance the field of plant metabolic engineering and pave the way toward developing more economical and sustainable bio-based products.
Over the last 20 years, Dr. Stewart has secured approximately $25 million in research funding from industry and government agencies, including the Departments of Defense and Agriculture, the National Science Foundation, and the National Aeronautics and Space Administration. He holds three patents and is an author on over 250 journal articles, seven books, and numerous book chapters. In 2015, Dr. Stewart was elected as a Fellow of the American Association for the Advancement of Science.
Over the course of his time at UTIA, Dr. Stewart has looked to UTRF for assistance throughout the technology transfer process. He is the recipient of several grants through the UTRF Maturation Grant Funding Program and appreciates the active role UTRF plays in promoting University innovation and technology. Dr. Stewart extends that appreciation to UTIA, noting the University’s willingness to give him opportunities to think outside of the box, try new things, and solve problems that benefit society.