Researchers) KIKUCHI Yoshitomo, Senior Researcher, Microbial Ecology and Technology Research Group, Bioproduction Research Institute and Visiting Associate Professor, Graduate School of Agriculture, Hokkaido University, SATO Yuya, Senior Researcher, Environmental Function Engineering Research Group, Environmental Management Research Institute
- Elucidation for the first time of the mechanism by which insects and symbiotic bacteria help each other to detoxify an insecticide
- Identification of a symbiont’s gene as an important factor in insect resistance to an insecticide
- Potential for new pest control strategies targeting the insecticide degradation gene of symbiotic bacteria
Relationship between insects and symbiotic bacteria related to insecticide detoxification
Insecticides become increasingly critical for stable food supply amidst concerns about food shortages due to climate change and rapid population growth. Furthermore, it is also necessary to use insecticides to control hematophagous sanitary pest insects such as anopheline mosquitos (a malaria vector) and household pest insects such as termites and cockroaches.
However, abuse of a single insecticide can result in the emergence of insecticide-resistant pest insects. One of the well-known mechanisms for insecticide resistance is structural changes in insecticide-targeted proteins due to mutations in the insect’s genome. Symbiotic bacteria in insect bodies have also recently been found to play an important role in detoxification of insecticides, which confer insecticide resistance on host pest insects. However, the mechanism for insecticide detoxification via symbiotic bacteria had not thus far been elucidated.
The emergence of insecticide-resistant pests is an endless battle between humans developing insecticides and pests increasing their resistance. The development of new agents is very costly and time-consuming, so resistance should be prevented from developing in the first place. It makes understanding the mechanism of resistance development an important issue.
AIST researchers elucidated the insecticide resistance mechanism through interaction between pest insects and gut symbiotic bacteria in collaboration with Hokkaido University and Akita Prefectural University, and with the cooperation of the National Agriculture and Food Research Organization (NARO).
The mechanism of gut symbiotic bacteria involvement in the insecticide resistance of pest insects is not known. AIST worked with other institutions to investigate how the gut symbiotic bacteria of the pest insect stinkbugs detoxify insecticides and identified a symbiont gene essential for the detoxification. Symbiotic bacteria use this gene to quickly degrade insecticides that have entered the pest insect's body. It was found that the insecticide degradation product is highly toxic to the symbiotic bacteria, but this substance is non-toxic to the host pest insect, and the pest insect quickly excretes it out of its body. As a result, the symbiotic bacteria can detoxify insecticides and continue to live in the body of the pest insect. This research discovered that pest insects and symbiotic bacteria intimately interact in the insecticide detoxification process.