Indian Phytopathological Society 

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Dean W. Gabriel

Dean W. Gabriel

Dean W. Gabriel was born in Washington, DC, received his B.A., M.S., and Ph.D. degrees from Michigan State University, and was involved in some of the earliest research on the molecular basis of gene-for-gene interactions in Al Ellingboe’s lab. He subsequently served as research associate at Oregon State University and assistant professor at Oklahoma State University. Gabriel was hired at the University of Florida (UF) in 1984 as a bacterial geneticist and was immediately directed to focus on citrus canker disease. At the time, the state of Florida was engaged in a program to eradicate what it called a “form” of citrus canker. He applied a new technique at the time, RFLP, to demonstrate that the new disease “form” was quite distinct from known citrus canker strains, which he proposed to be reinstated into an entirely separate species, Xanthomonas citri. This research piqued his interest in exotic and emerging pathogens. He anticipated that Florida’s increasing population and incursions into agricultural areas would result in the continuous introduction of exotic pathogens into the state, and this triggered his efforts to design and obtain initial funding to build a Biological Safety Level 3 Plant Containment Facility, the first such facility in the state. He has served as scientific director of that facility since its founding in 1987.

In addition to the diagnostic advances made by early research in his lab, he identified and cloned the principal pathogenicity effector gene from X. citri that is responsible for eliciting the “canker” phenotype on citrus. His group demonstrated that the causal gene naturally occurred on a self-mobilizing plasmid in some X. citri strains and also demonstrated that this gene expressed an elicitor protein with plant nuclear targeting signals that causes most of the observed symptoms of citrus canker. The fact that the gene was on a self-mobilizing plasmid indicated that new citrus canker strains could arise by horizontal gene transfer. He served on the USDA Biotechnology Risk Assessment Panel in 1997 and managed the panel in 1998. In 2002, he set up a joint UF/USDA web site to highlight the science behind biotechnology risk assessment for experts and teachers and has assisted the Interdisciplinary Center for Biotechnology Research (ICBR) program efforts to educate high school teachers about biotechnology and recombinant DNA.

His past 7 years of research and teaching on exotic pathogens have been highly productive. He has been sought as an expert witness and consultant for canker (in Florida, Australia, China, and Oman), citrus greening (Florida), and citrus variegated chlorosis or CVC (Brazil). His activities gained the attention of NASA, and because of his perspective on risk assessment of introduced plant pathogens, he was invited to help with a risk assessment of soil samples that might be returned by spacecraft from Mars and to help develop the Mars return sample biocontainment protocol to be used by NASA. He served from 1998 to 2002 on the Brazilian CVC Functional Genomics Advisory Panel and learned about the first plant-pathogenic bacterial genome ever sequenced. CVC, also a USDA select agent not present in the United States, threatens to be much more serious than canker to the U.S. citrus industry. A similar disease, Pierce’s disease, now threatens the California grape industry and is a primary reason why viniferous grapes cannot be grown in Florida. His work on both diseases has resulted in his active participation for the last 5 years in California’s Pierce’s disease program.

He anticipated the introduction of citrus greening into the state and his program has been able to quickly respond to this emerging threat to citrus. His lab personnel and the UF Plant Containment Facility were the first in the state to be licensed by USDA to work with this select agent. This has already resulted in the identification of the ornamental plant orange jasmine as a hidden carrier for greening, greatly assisting the state’s control response. This has also resulted in funding by USDA-APHIS for a greening genome sequencing project, and his lab is among the first in the world to see greening genomic sequence data. He has assembled an international team of experts to annotate this genome. He has initiated a genomics web site (not yet public) for citrus greening.

He has served on several competitive grant review panels, including USDA National Research Initiative panels. In the past 7 years, he has received more than $2.9 million in grants, published 19 refereed articles in top-tier molecular journals, mentored four postdocs, chaired four Ph.D. and three M.S. committees, and served on several student committees. He has six patents that have been awarded or are in the process of application at this time. He has had two of his patent applications licensed from the UF Office of Technology Licensing and a third is in negotiations for licensing at this time. He is founder and president of a private company, Integrated Plant Genetics, Inc., that has licensed two UF technologies and is a client company at the UF Sid Martin Biotechnology Development Institute (BDI) in Alachua (www.ipgenetics.com).

He has been an important member of the plant pathology community and of his department. A hallmark of his research has been the practical impact of his molecular and basic research program. He participates in teaching Molecular Plant Pathology and has assisted in the reorganization of the department’s molecular biology classes, an important part of the curriculum. He has team-taught the foundational plant molecular and cellular biology class, Advanced Molecular Genetics, which has received solid reviews. The students especially appreciate his private industry perspective on the applications of genetic engineering in plants.