Theodor Diener, Who Found the Tiniest of Infectious Brokers, Dies at 102

Discovering one thing infinitesimally tiny isn’t simple. However it’s a lot more durable when the searcher doesn’t know what to search for.

Theodor Diener, a plant pathologist on the federal Agricultural Analysis Service, confronted that drawback when he started investigating spindle tuber illness, an ailment that makes potatoes scrawny and misshapen.

Dr. Diener, who was 102 when he died on March 28 at his dwelling in Beltsville, Md., labored for years to seek out the offender, ensuing within the discovery of the smallest identified infectious agent, which he named a viroid.

Spindle tuber illness, which was first recognized within the Twenties, generally causes disastrous penalties for crops. Research present that the ailment can decrease potato crop yields by up to 64 percent; solely strict quarantining, and in some instances destruction of total crops, can include this extremely contagious sickness. However even many years after the illness was recognized, scientists had been nonetheless unsure what brought on it.

Dr. Diener and colleagues like William B. Raymer on the analysis service, a part of the Division of Agriculture, spent many of the Nineteen Sixties making an attempt to unravel the puzzle.

They studied the pathogen in tomato crops, which they discovered had a far shorter incubation interval for tuber spindle illness than potatoes, and used cutting-edge strategies to determine that this infectious agent contained no proteins and that RNA, or ribonucleic acid, one of many constructing blocks of life, was essential to it.

Dr. Raymer left the analysis service for a job in non-public trade in 1966, and Dr. Diener “spent the subsequent 5 years isolating and characterizing the viroid, verifying his experiments, filling within the holes” and “making ready to fulfill the skepticism that typically greets proposals of latest, ‘unattainable’ ideas,” in response to a 1989 article in Agricultural Analysis journal titled “Tracking the Elusive Viroid.”

On the time, scientists thought that one thing as small as viroids, that are one eightieth the scale of many viruses, had been too minuscule to trigger an an infection.

Like viruses, viroids reproduce by invading wholesome cells and reprogramming them to duplicate the viroid’s genetic make-up as an alternative of the cell’s personal.

However viruses, which might be made from DNA or RNA, have a protecting coat made from proteins and encode proteins as soon as they’ve invaded cells. Viroids, in contrast, are made solely of RNA, wouldn’t have the protein coat and don’t encode proteins.

“Its technique of manufacturing illness is mainly completely different from that of all different viruses,” Dr. Diener stated at an international meeting of virologists in 1972.

After figuring out the viroid that brought on spindle tuber illness, he helped develop a take a look at to detect it. He went on to obtain the Nationwide Medal of Science from President Ronald Reagan in a Rose Backyard ceremony on the White Home in 1987.

William Haseltine, a virologist and former professor at Harvard Medical College who has written a series of articles about viroids for Forbes journal this yr, stated in a cellphone interview that Dr. Diener “found an entire new department of life, in all probability essentially the most basic department of life, no less than to my definition.”

Dr. Diener’s discovery has implications for scientific understanding of the origins of life and for medication, contributing to breakthroughs like using messenger RNA to develop vaccines for Covid-19, Dr. Haseltine stated.

Since Dr. Diener’s discovery, scientists have recognized greater than 30 completely different viroids that trigger ailments in crops, just like the avocado sunblotch, coconut cadang-cadang, pear blister canker and hop latent viroids, which might be devastating to hemp and hashish crops.

Theodor Otto Diener was born on Feb. 28, 1921, in Zurich, the one youngster of Theodor and Hedwig (Baumann) Diener. His father was a postal employee, his mom an accountant.

As a baby he was fascinated with animals and saved a colony of mice, a turtle and a canary, a lot to his mother and father’ discomfort. His father, he wrote in a self-published memoir, “Of People, Humanoids, and Viroids” (2014), didn’t admire his consuming curiosity in “small residing issues.”

He “typically shook his head in disbelief after I was enthusiastically holding forth — describing attributes of some tiny insect, worm or fungus,” Dr. Diener wrote.

Dr. Diener did airplane upkeep for the Swiss Air Power throughout World Struggle II, and in 1948 he accomplished his doctorate in biology on the Swiss Federal Institute of Expertise.

He emigrated to the USA in 1949 and, after a quick time in New York Metropolis, moved to Spokane, Wash., for a job at Washington State Faculty (now Washington State College). He moved to Maryland to work with the federal government analysis service a few decade after coming to Washington.

Dr. Diener’s first marriage, to Shirley Baumann, resulted in divorce. In 1968 he married Sybil Fox, who died in 2012.

He’s survived by three sons from his first marriage, Michael, who confirmed the dying, Theodore and Robert; 5 grandchildren; and three great-grandchildren.

Dr. Diener’s different honors embody his election to the National Academy of Sciences and to the American Academy of Arts and Sciences. In 1987, he acquired the Wolf Prize in agriculturea $100,000 award given by the Wolf Basis in Israel.

Viroids could also be rather more than agricultural pests. Research suggests that they existed on the earliest phases of life on Earth, unnoticed till Dr. Diener took up the search.

Dr. David A. Relman, a microbiologist at Stanford College, wrote of Dr. Diener in an electronic mail, “His discovery of viroids and their position in plant ailments helped to disclose the position of RNA molecules in primary organic processes, and doubtlessly within the origin of life itself.”

Ashley Shannon Wu contributed reporting.