Genetically-engineering a protein from wasp venom into a fungus used in sustainable pest control increases its effectiveness against two major pests of a number of economically-important crops.
In a study carried out at the Chinese Academy of Sciences, researchers inserted a protein known as VRF1, derived from the venom of the parasitoid wasp Microplitis mediator, into the genome of Beauveria bassiana, a fungus which is commonly applied as an ecologically-friendly pesticide.
The protein had already been identified as a promising prospect, as it had been found to suppress the expression of antimicrobial peptides, a form of immune response which is used by the cotton bollworm (Helicoverpa armigera) and other moth pests against the offspring of parasites such as M. mediator growing inside it.
Tests by the scientists showed that the dose of genetically-engineered B. bassiana required to kill H. armigera was reduced 2.36-fold compared to using the non-engineered type, and the time needed to kill the pest by 16%.
Even better results were seen when the novel pesticide was tested against another prominent global pest moth, the fall armyworm (Spodoptera frugiperda), with 3.45-fold reduction in lethal dose required and 27% reduction in time needed. However, S. frugiperda is an invasive species outside the range of M. mediator, which could complicate field application of B. bassiana modified in this way against this species.
Exploiting the biology of two species
Fungal pesticides such as B. bassiana are set to play an increasing role in controlling the world’s agricultural pests. At present, their main drawback is lower efficacy than conventional chemical pesticides, meaning that the research offers considerable promise.
“Genetically engineered bioinsecticides, including recombinant entomopathogenic fungi, have been regarded as a breakthrough to rapidly control pests. Deep knowledge of parasitoid wasps allows us to take advantage of this natural enemy of pest insects beyond raising them for field release,” the researchers wrote in the journal Applied and Environmental Microbiology.
“This result provides a new strategy regarding which venom protein of parasitoid wasps can become part of the arsenal with which to equip entomopathogenic fungi.”
