A virus that causes mutations in insects to facilitate its spread

2024-02-23 07:30:49

To spread, viruses affecting plants need a vector and this is often an insect. But there is more surprising: Chinese researchers have demonstrated how the rice stripe virus was capable of affecting the genes of insects in order to enlarge their wings and thus promote its dissemination!

This discovery is important because it allows us to better understand the coevolution of plant viruses with their insect vectors, an essential element for reducing the impacts of epidemics caused by these viruses on agricultural production.

A virus that only targets males

The fact that the dimorphism of the wings of insect vectors is a determining factor for the dispersal of viruses over long distances and large areas is a known phenomenon.

On the other hand, if the effects of these viruses on wing plasticity are also present, the molecular mechanisms at work remain poorly understood.

In study recently published in the journal PNASa team of Chinese researchers[1] explains the mechanism by which the rice stripe virus (also called rice stripe virus, or RSV), very widespread in Asia, directly modifies the size of the wings of Laodelphax striatellus, an insect of the Delphacidae family.

They notably discovered a particularity: RSV exclusively induces modifications on the wings of male individuals. What is the cause ? A gene regulating wing developmentnamed “Encounter” which acts, at the larval stage, on insulin transduction and which is strongly expressed in infected males.

Viruses, not always enemies and sometimes vectors of evolution

In addition to the direct applications in plant pathology and agriculture, this study reminds us to what extent these concentrates of genetic material and proteins that are viruses are too often misunderstood. According to another studyat least 1.7 million still unknown viruses are believed to be present in nature!

You should also know that although viruses are intracellular parasites that use the genetic material of a cell to replicate, their effects are not necessarily harmful. We can even say that they play a major role in the process of evolution.

Indeed, we know that after having infected a cell, certain viruses are capable of going dormant or even integrating their genome into that of the cell. In the human genome, there would be approximately 500,000 retroviral genomes, acquired more than 150,000 years ago. Although most of these genes of viral origin are no longer expressed today, certain sequences still play a major role in our lives. This is particularly the case of a viral envelope protein present in placental tissue and which makes exchanges possible between the blood of the mother and that of the fetus, just that!

Coming back to plants, it has also been proven that certain plant viruses described as persistent were beneficial for the plant. For example, the presence of a persistent partitivirus in pepper limits the spread of a pathogenic virus called cucumber mosaic. And sometimes, by accident, this presence of persistent viruses even leads to integration into the plant genome.

We still have a lot to learn from the study of viruses and their interactions with living things. It is certain that the years to come will be rich in lessons!


[1] University of Chinese Academy of Sciences et Institute of Zoology (Chinese Academy of Sciences)

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