It is with great sadness that we report the passing of Dr. Theodor O. Diener, Ph.D., Emeritus Professor of Cell Biology and Molecular Genetics and Emeritus Distinguished University of Maryland Professor, at the age of 102. Dr. Diener was a luminary in the field of virology and molecular biology as the discoverer of the first circular RNAs, the plant pathogens known as viroids. Dr. Diener also made the seminal discovery that non-coding RNAs could cause devastating plant diseases while functioning simply as an RNA.
Born in Switzerland in 1921 and emigrating to the USA in 1946, he joined the USDA in Beltsville, Maryland in 1959 where he discovered that the causal agent of potato spindle tuber disease was not a virus as expected, but a tiny 359 nucleotide circular RNA. This finding meant that non-coding RNAs could by themselves significantly impact how cells functioned, predating by decades similar findings by others. In 1989, Dr. Diener was named a Distinguished Professor at UMCP where he became a Distinguished Professor Emeritus in 1994 after retiring and was later inducted into the College of Life Sciences Circle of Discovery in 2007. In his long and illustrious career, Dr. Diener published 120 peer-reviewed articles, 53 chapters in books, 2 books on viroids, and lectured worldwide. Dr. Diener was the recipient of numerous prominent awards, including membership in the National Academy of Sciences, the Campbell Award, the Alexander von Humboldt Award, the Ruth Allen Award, the Wolf Prize in Agriculture and the National Medal of Science.