Plant virus spreads by making life easy for crop pests

October 30, 2008,
Deformed and defenseless. New research shows how a virus deploys a single molecule, βC1, to turn a healthy tobacco plant (left) into a deformed and sterile one (right). The molecule also tricks the plant into lowering its defenses against the pests that spread the virus.

(PhysOrg.com) -- In 752, Japanese Empress Koken wrote a short poem about the summertime yellowing of a field in what is thought to be the first account of a viral plant disease. More than 1,250 years later, scientists concluded that the virus Koken described was part of the particularly insidious geminivirus family that continues to decimate tomato, tobacco and cotton crops worldwide. Now, new research shows how cunning an enemy one of these ancient viruses can be, manufacturing a protein that deforms and sterilizes plants and at the same time wrecks their defenses against the pests that spread the disease to others.

Researchers at The Rockefeller University have found that βC1, a toxic protein produced by the tomato yellow leaf curl China virus (TYLCCV), mimics the behavior of one of two different molecules that govern the development of leaf shape and vein structure. In doing so, it throws the plants off course, causing the unseemly curling and crumpling of leaves and the production of sterile flowers. But it also suppresses the plants’ jasmonic acid response, a defense mechanism against pests feeding on the plants. The result is that the pests — in this case whiteflies that plague tobacco plants — flourish in the diseased crop, spreading the virus faster and faster. Nam-Hai Chua, Andrew W. Mellon Professor and head of the Laboratory of Plant Molecular Biology, and his colleagues published the work in Genes and Development.

“This is a new way to look at the relationship between viruses, plants and vectors,” says Jun-Yi Yang, a postdoc in Chua’s lab who did the research. “If you just look at viruses and host plants, you can’t explain why the whiteflies tend to congregate on infected plants. Our research explains how the disease can spread so fast.”

The researchers inserted a gene that produces βC1 into Arabidopsis plants, model organisms for studying plant biology. The plants grew up with symptoms very similar to those of tobacco plants infected with TYLCCV. Yang and colleagues found that these mutants had the same problems as plants that overproduced a protein known as Asymmetric leaves 2 (AS2), which along with Asymmetric leaves 1 (AS1), regulates crucial elements of a plant’s development. In effect, βC1 poses as AS2 and interacts with AS1, upsetting the healthy development of plants. But it also weakens the response of genes that normally boost the jasmonic acid defense against the threat of an invasive pest, the researchers found.

The discovery of how a toxic protein manipulates the relationship of the plant and the whitefly to favor the virus could lead to a more comprehensive strategy for fighting the disease. “You need to fight against both viruses and insect vectors,” Yang says. “If you can increase the jasmonic acid response, you’ll have a better chance against whiteflies.”

Citation: Genes and Development 22: 2564–2577 (September 2008)

Provided by Rockefeller University

Explore further: At last, butterflies get a bigger, better evolutionary tree

Related Stories

At last, butterflies get a bigger, better evolutionary tree

February 15, 2018

For hundreds of years, butterfly collecting has often inspired a special kind of fanaticism, spurring lengthy expeditions, sparking rivalries and prompting some collectors to risk their fortunes and skins in their quest for ...

Plants feel the heat

February 13, 2018

It's not just humans and animals that suffer when the mercury rises, plants feel the heat too. Heat stress is a major issue in agriculture and can significantly reduce crop yield. Even small increases in temperature can affect ...

Butterfly gardens offer some hope for pollinators

February 15, 2018

Butterflies will use gardens planted to attract them, according to a new study from the University of Georgia. But the researchers cautioned that butterfly gardens can sometimes have a downside by exposing caterpillars to ...

Ravaged by a poorly studied disease, cacao trees are dying

February 15, 2018

Picture this: It's Valentine's Day, and you head out to buy some pralines. Except you can't find any. No matter which store you visit, gummy bears and hard candy have taken the place on the shelves where the chocolate hearts ...

Hunting is changing forests, but not as expected

February 15, 2018

When it comes to spreading their seeds, many trees in the rainforest rely on animals, clinging to their fur or hitching a ride within their digestive tract. As the seeds are spread around, the plants' prospects for survival ...

Recommended for you

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.