Toxin that boosts the virulence of Metarhizium anisopliae discovered by scientists
Researchers from the Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, and the Department of Entomology at the University of Maryland in the United States have discovered a neurotoxin that can enhance the virulence of an insecticide, providing important material for the application of this insecticide, as well as for studying the mechanism of action of fungal insecticides and the molecular mechanism of fungus-insect interactions. The results of this study were published in the journal Nature Biotechnology.
The authors of the article are Professor Raymond J St Leger of the University of Maryland and Dr. Wang Chengshu, leader of a "Hundred Talents Program" research group at the Institute of Plant Physiology and Ecology. Dr. Wang Chengshu's research areas mainly include functional research on pathogenic genes of entomopathogenic fungi, the molecular mechanism of fungus-insect interactions, the molecular mechanism of strain degeneration and senescence in filamentous fungi, and the developmental biology and active ingredient metabolic pathways of Cordyceps fungi.
Insecticides are a class of pesticides mainly used to control agricultural pests, and some can also be used for public health and epidemic prevention as well as pest control for livestock, industrial raw materials, products, and the like. They have a long history of use, large application volumes, many varieties, and remarkable control effects.
Metarhizium anisopliae is an important insect-parasitic fungus belonging to the genus Metarhizium in the subdivision Deuteromycotina. Its infection process in the host includes adhesion, spore germination, penetration of the insect body, development within the body, and causing death. This process is the combined result of the physiological and biochemical actions of substances such as appressoria, cuticle-degrading enzymes, and destruxins. Because of its broad host range, strong pathogenicity, non-toxicity to humans, livestock, and crops, no residual toxicity, ease of production of fungal preparations, and long persistence, it has broad application prospects.
However, because the toxicity of this fungus is relatively low, its application in pest and disease control is affected. In this article, the researchers found that an insect-specific neurotoxin from the yellow fat-tailed scorpion (Androctonus australis) can enhance the toxicity of this fungal insecticide, and they elucidated the principle of this effect.
They found that high-level expression of this specific neurotoxin can enhance the fungus's toxicity to tobacco hornworm (Manduca sexta) caterpillars by 22-fold, and its toxicity to adult yellow fever mosquitoes (Aedes aegypti) by 9-fold, and it also does not impair host specificity.
These research results provide important material for understanding the mechanism of action of fungal insecticides and the molecular mechanism of fungus-insect interactions.