An artificial protein with insecticide action can be a powerful tool for the control of whitefly, a plague that attacks crops like soybeans, cotton, kidney beans and tomato. Biotechnology tools have allowed scientists of Embrapa Hortaliças in Brazil’s Federal District to develop a protein formulated by the association of one toxic protein and another belonging to the begomovirus, a micro-organism transmitted by the whitefly.
The artificial protein is obtained by infusing the protein coat of the virus – which is responsible for forming a wrap that coats the genetic material of this micro-organism – with a toxic molecule isolated from spider poison.
This molecule has a lethal and specific effect since it reaches the hemolymph (a liquid that circulates in the vases of invertebrate animals and is analogous to the blood of vertebrate animals) and the central nervous system of the insects, causing paralysis.
In general terms, the hypothesis is that when the insect ingests the fusion protein, the coat transports the toxic molecule of the digestive system into the circulatory system, and then to the nervous system, a place where blockade of neurotransmitters causes spams in the insect, and eventually results in its death.
Biologist Erich Nakasu, an analyst with the Research and Development department of Embrapa Hortliças, affirmed that there “are two possibilities outlined to achieve the toxic effect: developing a plant that expresses the fusion protein, being a source of the toxic product or a food for the insect with an artificial diet.”
“The specific toxin is being evaluated by the project. It is extracted through the spider poison, has a specific action and causes damage only to insects. In vertebrates, in general, including humans, this toxin does not cause any harmful or deleterious effect,” explained the biologist. All such tests, he stressed, follow the norms set by the National Technical Commission of Biosafety.
Currently, the trend is to test the effectiveness of fusion proteins in controlling plague. Nevertheless, the application of this methodology in case of whitefly is new and, if the results are positive, can mean a big advance in integrated management to check this plague, Currently, the plague is being tackled through chemical control, which can be harmful for sustainable agriculture.
The success of the research was largely attributed to the expertise of the staff. Nakasu, while pursuing his PhD studies at the Newcastle University and the Durham University in the United Kingdom, worked on the evaluation of a fusion protein obtained through a combination of poison of any spider specie with a substance found on the flowers of the family Amaryllidaceae. However, on the occasion of target control, they were aphids. He also analyzed the effect of this fusion protein on memory and learning capacity of beneficial insects and non-targets, such as bees, and concluded that it did cause any complication for these insects.