Scientists have tapped into a new resource in the ongoing fight against viruses transmitted by mosquitoes and other arthropods.

In a new study, researchers have uncovered for the first time that a plant hormone is the major host factor to mediate the attractions between insect vectors and infected plants.

This discovery may lead to a new strategy to control viral diseases by targeting either the viral effector protein or the host hormone required for attracting disease vectors to the infected host for virus transmission.

The study was led by a team of scientists from the University of California, Riverside and Tsinghua University in China, who uncovered molecular mechanisms that the cucumber mosaic virus uses to manipulate plants to make them release odors that attract aphids, which transmit the virus.

“Recent studies have shown that pathogen-induced vector attraction can be odor-dependent, suggesting, presumably, the presence of a specific mechanism by which pathogens manipulate the host’s ability to emit odors that could attract disease vector,” the researchers write in the study.

Diseases like the cucumber mosaic virus are often caused by pathogens that are transmitted by disease carrying arthropods. 

The emergence and success of these pathogens are shaped by molecular interactions between both the host and the arthropods.

Plants utilize RNA interference (RNAi) to protect themselves against diseases like the cucumber mosaic virus.

Shou-Wei Ding, Ph.D., a professor of plant pathology and microbiology at UC Riverside, previously discovered that the 2b protein in the cucumber mosaic virus blocks the plant from launching antiviral RNA interference.

Ding was able to build on the previous research by finding some pathogens that can manipulate plants and animals to cause them to release odors that are attractive to the mosquitoes and aphids that transmit the pathogen.

Until Ding’s study, the molecular mechanism underlying the host manipulation was unknown.

The science team found that the aphid-borne cucumber mosaic virus employs the 2b protein to suppress a specific hormone pathway in plants, making the aphid vectors more attracted to the diseased plant.

The cucumber mosaic virus, which is found worldwide, spreads rapidly and can cause irreversible damage to plants, including many used in landscaping and vegetable crops like tomatoes, peppers, lettuce and cucumbers.

However, the researchers said they can harness the virus to produce more disease resistant vegetables and larger crop yields for farmers.

This represents the first time a viral effector protein has been seen as attracting insect vectors to feed on plants through odor.

According to the study, the cucumber mosaic virus is one of the most successful plant pathogens as it can infect more than 1,200 different types of plant species.

The study was published in Cell Research.