Washington State University virologists state that the iris yellow spot virus posing an ever-growing danger to onion crops, as it is evolving and spreading. Nearly 20 years ago, Hanu Pappu examined wilting onion plants collected from a field in Grant County, Washington, by fellow WSU scientists Gary Pelter and Lindsey du Toit.
When running a molecular test, followed by genetic sequencing, Pappu found that Iris yellow spot virus, which had not been previously reported in Washington, was infecting and killing the onions.
Named for its original host plant, Iris yellow spot has caused significant damage to onion crops around the world. Though the virus is known to infect onion crops since the beginning of 1990s in southern Idaho and Oregon, scientists were baffled by the sudden resurgence and rapid spread of the virus in the early 2000s.
Pappu and his research colleagues set out to understand the diversity of the virus, as well as its evolution and possible reasons for its global spread, using a rapid molecular test. They learned that Iris yellow spot exists as two distinct strains due to differences in one of its genes. Their test can quickly identify which of the strains is involved in an outbreak.
Source - https://www.freshplaza.com