University of Illinois researchers have confirmed the first report of a potential new virus belonging to the genus Marafivirusin switchgrass, a biomass crop being evaluated for commercial cellulosic ethanol production.

The virus is associated with mosaic and yellow streak symptoms on switchgrass leaves. This virus has the potential of reducing photosynthesis and decreasing biomass yield. Members of this genus have been known to cause severe yield losses in other crops. For example, Maize rayado fino virus (MRFV), a type member of the genus, has been reported to cause yield reductions in corn grown in Mexico, Central America and South America.

“Viral diseases are potentially significant threats to bioenergy crops such as Miscanthus x giganteus, energycane and switchgrass,” said Bright Agindotan, research associate working in Carl Bradley’s laboratory as part of the Energy Biosciences Institute (EBI) located in the Institute for Genomic Biology at the U of I. “Our team at EBI has been charged with identifying potential pests and pathogens of these bioenergy crops.”

Until recently, little has been known about viruses in these bioenergy crops. Agindotan said most plants can be infected with multiple viruses, making it a challenge to know which viruses to start screening for, especially when only a few viruses have been reported to affect these crops.

Agindotan developed a method that allows for the identification of a virus without prior knowledge of it. He successfully used sequence-independent amplification (SIA) to identify RNA viruses. This is the first time it has been fully described and used for plant virus identification.

The method involves virus partial purification for a small amount of infected leaf tissue, extraction of viral RNA, random amplification, cloning, sequencing, and searching databases to identify the virus.