A 1,000-year-old virus recovered from an ancient Native American settlement is the oldest plant virus ever found.
Centuries ago, the ancestral Puebloan people living in what is now the southwestern United States grew crops such as maize (corn) and squash. In the 1970s, excavations at a Puebloan site known as Antelope House, which lies deep in an Arizona canyon, uncovered maize cobs, kernels and husks.
Marilyn Roossinck at Pennsylvania State University in University Park and her colleagues recovered three nearly complete genomes of a previously unknown RNA virus from cobs dating to about ad 1000. They named the new virus Zea mays chrysovirus 1 because it is related to the Chrysoviridae-like family of viruses, which can infect plants and are transmitted across generations by seeds. The researchers also found a close relative of the new virus in modern maize. The modern virus’s RNA sequences differed from the ancient sequences by only about 3%.
The previous record holder for oldest plant virus, a barley stripe mosaic virus found in North African barley, was about 750 years old.