|Chay, Catherine - MONSANTO CORPORATION|
|Gunasinghe, U - CORNELL UNIVERSITY|
|Dinesh-Kumar, S - IOWA STATE UNIVERSITY|
|Miller, W - IOWA STATE UNIVERSITY|
Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 21, 1996
Publication Date: N/A
Interpretive Summary: Barley yellow dwarf is the most economically damaging viral disease of cereal crops worldwide. The disease is caused by a group of related luteo- viruses collectively known as barley yellow dwarf virus (BYDV). These viruses are efficiently transmitted by aphids in nature. Currently there are no methods to effectively control this disease. We are currently inves- -tigating how the virus interacts with its aphid vectors. By understanding the factors that allow aphids to pickup & transmit the virus it may be possible to design strategies that interfere with the transmission process. The objective of the work described in this manuscript was to investigate the role of several virus proteins in aphid transmission & plant infection. Viruses that contained mutations in various proteins were fed to aphids & then the aphids were allowed to feed on plants. The ability of the mutant viruses to move through the aphids & into the plants was monitored. Results sindicated that 1 of the proteins that makes up the virus shell is required for the virus to pass into the aphid salivary glands. This protein is not required for the virus to pass through cells of the aphid gut system. The protein also influences the amount of virus that accumulates in an infected plant. Another virus protein that is found in plants, but not aphids was not directly involved in aphid transmission. However it was required for the virus to cause an infection in plants. This is the first information that demonstrates the function of two luteovirus proteins. An understanding of how the virus moves through its pahid vector & what is required for in- fection of a plant host is necessary for the development of novel strate- gies to protect plants either by preventing transmission or preventing the virus from infecting a plant after being delivered by an aphid.
Technical Abstract: The barley yellow dwarf luteoviruses are obligately transmitted by aphids in a circulative nonpropagative manner. The ability of the virus to attach to and be transported across three cell membrane barriers is determined by properties of the luteovirus capsid proteins. The capsid contains two proteins, a major 22-kDa protein and a minor 72-kDa protein translated as a areadthrough of the 22-kDa protein. Barley yellow dwarf virus carrying various mutations within the readthrough domains were tested for their ability to circulate in and be transmitted by aphids. The results demonstrates that the readthrough domain is required for transport of virus through the salivary gland of aphids. It is not required for virus transport through the hindgut cell, nor is it required for systemic infection of plants. It does however influence the accumulation of virus in infected plants. The 17-kDa protein, encoded by an open reading frame contain with in the coat protein ORF was also found to be required for the systemic infection of plants.