Dr. Robert E. Davis, Research Leader, Molecular Plant Pathology Laboratory, at the USDA Beltsville Agricultural Research Center, member of the National Academy of Sciences, and discoverer of the spiroplasma genus of plant microbes, passed away peacefully in his sleep on July 18, 2019. From the early 1970s up to and including the time of his passing, Dr. Davis was one of the leading researchers and innovators in the field of phytoplasmas and spiroplasmas, plant pathogenic cell wall-less bacteria that evolved from walled bacterial ancestors and which possess genomes that are among the smallest known in bacteria, approaching the minimal sets of genes required for cellular life and parasitism in plants and insects.
Born in Brooklyn, N.Y. on January 27, 1939 to Robert S. and Cecelia Davis (neé Hall), Dr. Davis was raised in Warwick, where he attended Warwick High School and met his future wife of 58 years, Maryann Davis (neé Starr). He attended the University of Rhode Island, graduating summa cum laude with a Bachelor of Science in botany in 1961. He was awarded his Ph.D. in plant pathology from Cornell University, Ithaca, N.Y. in 1967. Following a National Research Council Postdoctoral Fellowship with the USDA-ARS in Beltsville, Maryland from 1966 to 1967, he accepted a position as a research scientist in the Plant Virology/Molecular Plant Pathology Laboratory, where he remained as a full-time government scientist until his passing, a career that spanned 52 years.
Dr. Davis developed several new scientific concepts and led the way toward discovery of an entirely new taxon of pathogens. In 1971, while looking for the causative agent in corn stunt disease, Dr. Davis was the first to discover a previously unidentified, extremely narrow helical and motile filament that was present in every diseased culture and in no healthy culture. In a 1972 paper in Science reporting his findings, Dr. Davis coined the term “spiroplasma” for the corn stunt and other yet-to-be-discovered wall-less bacteria having helical cell shape. Shortly thereafter, the citrus stubborn wall-less microbe, previously reported as a non-helical MLO, was recognized as a helical microbe, and the term “spiroplasma” was adopted as a new genus name. Dr. Davis’s discovery of the spiroplasma class of organism is recognized as among the top ten milestones of the past century in plant pathology and opened an entirely new field in which diverse spiroplasma pathogens have subsequently been found. Today, following work in Dr. Davis’s laboratory and others, diverse Spiroplasma species are known as insect-transmitted pathogens of plants, as symbionts in ticks and diverse insects, as lethal pathogens in crustaceans such as some shrimp and crab, and as possible inhabitants of jellyfish, a deep-sea chiton, and a hadopelagic zone sea cucumber; and some can present risk of human infection.
Most recently, Dr. Davis and his colleagues recently published the first completely sequenced genome of the corn stunt spiroplasma, Spiroplasma kunkelii, as well as the first completely sequenced genomes of the only other known plant pathogenic spiroplasmas, S. citri and S. phoeniceum. Important new insights into numerous plant diseases caused by poorly understood microbes were developed through national and international collaborative research teams led by Dr. Davis and his colleagues and whose contributions continue to impact basic science and provide solutions to economic problems in agriculture in the United States and elsewhere. During his career, Dr. Davis mentored many young scientists and students and helped establish molecular plant pathology laboratories worldwide, leaving an impressive legacy to the future of plant pathology.
For his work and leadership in advancement of the plant sciences, Dr. Davis has received numerous awards and recognition, including the following of which he was most proud:
1983--Fellow Award, Washington Academy of Sciences
1983--Washington Academy of Sciences Award; Outstanding Research in Biological Sciences
1985--Fellow Award, American Phytopathological Society (APS)
1997--Agricultural Research Service (ARS, USDA) Outstanding Scientist of the Year Award
1998--USDA Silver Plow Award, Secretary of Agriculture's Award for Personal/Professional Excellence
2001--APS Ruth Allen Award "For Outstanding Contributions to the Science of Plant Pathology"
2003--Republic of Lithuania State Decoration, Order of the Knight's Cross, For Service to Science in Lithuania, presented by President Adamkus
2003--Distinguished Member, the Senior Scientific Research Service, USDA
2004--Presidential Rank Award, Distinguished Senior Professional, presented by President Bush
2005--Elected to the USA National Academy of Sciences
2005--Qilu Friendship Award, Provincial Government of Shandong, China.
2007--Fellow, American Association for the Advancement of Science (AAAS)
2008--Science Hall of Fame Inductee, USDA-ARS
2009--Distinguished Service Award, American Phytopathological Society, Potomac Division
2012--Emmy Klieneberger-Nobel Award For Outstanding Research in Mycoplasmology,
awarded by the International Organization for Mycoplasmology
Dr. Davis moved to Crofton in 1970, where he was an active member of the Crofton Swim and Tennis Club.
He is survived by his wife Maryann, his brother and sister-in-law, Jim and Judy Davis of Canterbury, Conn., his sons, Peter and Michael, his grandchildren, Katherine, Sabrina, Zach and Jake, his niece Jill Brennan, his nephew Jeffrey, and his grandnephews Birch, Alden and Rex.
He was laid to rest on Saturday, Aug. 3 at Our Lady of the Fields Catholic Church, 1070 Cecil Avenue South, Millersville, MD 21108.
The family requests that donations be made to a charity of the donor’s choice.
