Double manipulation for efficiency
Plant infecting viruses use ingenious techniques for optimal distribution. As show scientist in Science Advances that TYLCV manipulates both its host plant and its distributor.
Plant infecting viruses cause lots of damage. It is estimated that at least 30 billion dollars of crops are lost on an annual basis due to viruses spread by insects. By studying the tactics of these viruses, researchers hope to find ways to better protect those crops.
In this way researchers found that viruses manipulate plants to produce volatile compounds that attract insects. Those insects ingest the virus while they are feeding on the plant. And they give the virus to the next plants they visit. Viruses also can manipulate those insects it catches a ride from, so that those insects find non-infected plants more attractive than infected plants.
Infected plants release more beta-mycrene, making them wildly attractive to white flies
One of the big virus propagators are white flies. And one of the viruses it spreads is TYLCV. TYLCV causes lots of damage in tomato plants. Intriguingly, a non-infected white fly is more attracted to infected plants. While an infected white fly prefers non-infected plants. The researchers decided to investigate this in more detail.
First the researchers investigated which volatile compounds the infected and non-infected tomato plants release. This resulted in a list of twelve volatile compounds that the infected and none-infected plant released in different quantities. When the researchers let the white fly choose between those substances, the white fly showed a preference for beta-mycrene. A compound that infected plants release double the amount of.
The ultimate test was if the white fly preference also holds in practice. For this the researchers created plants that did not produce any beta-mycrene. The white flies did not prefer those plants. No matter if they were infected or not.
TYLCV also manipulate white flies, after infection they no longer smell beta-mycrene
Subsequently the researchers studied the white fly. They were especially interested in which odour receptor recognises beta-mycrene. Six white fly odour receptors were inactive after infection with the virus. The researchers permanently inactivated those receptors one by one. After turning off receptor OR6 the white flies did no longer preferred infected tomato plants.
In not infected white flies OR6 is normally turned on. This explains its preference for tomato plants that release beta-mycrene. But after infection the virus turns OR6 off. Then white flies no longer smell beta-mycrene, which makes infected and non-infected plants equally attractive.
TYLCV is manipulating therefore both the plants and white flies so it can spread itself optimally. Plant breeders and farmers can use this knowledge. By for example, breeding tomato plants that can no longer produce any beta-mycrene. Or by luring white flies away with the smell of beta-mycrene.
Literature
Peng Liang et al., (2025) A plant virus manipulates both its host plant and the insect that facilitates its transmission. Sci. Adv. 11, eadr4563. https://www.science.org/doi/10.1126/sciadv.adr4563
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