Portable DNA sequencer “quickly and accurately” diagnoses wheat viruses

Scientists believe the genome sequencing will lead to higher wheat yields around the world.

A group of scientists in Kansas, based at The Agricultural Research Service of the US Department of Agriculture (USDA-ARS) and Kansas State University, have developed a new technology that makes it possible to rapidly identify viruses in wheat fields with a higher level of accuracy.

It is said that blast, a disease that results from a fungus that infects the wheat spikes in the field, turning the grain to inedible chaff, cause significant loses in wheat crops. Recently, Bangladesh was devastated by an invasion of South American races of wheat blast fungus, which occurred for the first time in the country in 2016. The disease spread to an estimated 15,000 hectares (16 percent of cultivated wheat area in the country) and resulted in yield losses as high as 100 percent.

Diagnosis of crop disease is considered crucial but traditional methods rely on the expertise of pathologists, who in turn rely on the physical appearance of disease symptoms, which can be similar to damage caused by other factors, such as nutrient deficiencies or environmental elements. Pathologists also experience difficulty detecting coinfections and pathogens that do not infect aerial parts of the plant.

Rapid detection is also considered a key issue for identifying unknown pathogens during an outbreak, as was made clear during the wheat blast fungus outbreak in Bangladesh.

The Kansas scientists collected four wheat samples from western Kansas and used a new “harmonica-sized” DNA sequencer and a computer programme to quickly detect three different viruses in the samples. The results suggested that the samples contained a new virus strain.

The scientists are now working on improving the technique so that it can be used in field applications. Their research, described in ‘Wheat Virus Identification Within Infected Tissue Using Nanopore Sequencing Technology,’ published in the September 2019 issue of Plant Disease, is the first report of using the new portable DNA sequencing technology for wheat virus identification. These results hope to have broad application to plant and animal disease identification and field diagnostics technology in the near future.