Bemisia tabaci: How the world's only "super pest" came to be

Bemisia whitefly is recognized as the world's second largest pest by the Food and Agriculture Organization of the United Nations. It is also the only agricultural pest called a "super pest" so far. It can spread more than 300 plant viruses, and more than 600 species of plants are its food.

Bemisia tabaci

In the wonderful evolutionary process of nature, in order to resist the invasion of insects, plants will also produce some toxic substances to protect themselves, such as phenolic sugar, which is a common plant defense compound that can inhibit the growth and development of insects. However, if too much phenolic sugar accumulates in the plant, it will also be detrimental to the growth and development of the plant itself. Therefore, plants will use the malonyl transferase in their bodies to degrade phenolic sugar and make it non-toxic.

Zhang Youjun's team found that the reason why Bemisia whiteflies are so harmful is because they "steal" the detoxification gene in plants - malonyl transferase (PMaT1).

This means that genes that originally existed only in plants or a few fungi have now been transferred to insects, and this gene has not only been inherited from generation to generation, but also plays an important role - degrading the phenolic sugars that plants use to protect themselves. This process is called horizontal gene transfer, which probably occurred between 35,000 and 86,000 years ago. Compared with vertical gene transfer, that is, passing from parents to offspring, horizontal gene transfer breaks the boundaries of kinship and makes the possibility of gene flow more complicated.

This discovery reveals how insects use horizontally transferred genes to overcome the host's defenses, opens up a new perspective for exploring the laws of insect adaptive evolution, and also provides a new idea for the development of a new generation of target gene-guided precise green field control technology for whiteflies. (Song Yajuan)

Scientific review: Guo Zhaojiang, Chinese Academy of Agricultural Sciences