Team:NYMU-Taipei/Project-Background

What is the problem?



Chemical insecticides:

Although chemical insecticides have improved the lives of countless human beings by controlling the population of both agricultural and urban pests, since the second half of last century, the numbers of insecticide resistant pests have been rising at an alarming rate [1]. Some would argue that as researchers and chemical pesticide companies develop new insecticides, the resistance couldn’t possibly catch up. In reality, the amount of insecticides applied is actually proportional to the increase in resistance in the target pest population [2], [3]. This means if no action is taken to change the status quo, the ongoing population control of insect pest will become even more of a struggle.

Problems on implementing M.anisopliae in field



Biopesticides, including insecticidal plant extract, bacteria, and fungi, are some of the more popular alternatives to chemical pesticides. Currently, the biopesticides that are the most widespread, in terms of usage, are the entomopathogenic-fungi insecticides[4]. Certain species of entomopathogenic fungi are capable of targeting a small range of hosts, making them the ideal solution to many regional insect pests. However, these biological control agents come with highly variable outcomes due to the variation in environmental (e.g. temperature and humidity) and host (e.g. nutrition and immune response) conditions [5].

Many researchers have tried to improve these fungal insecticides through biochemical or genetic means [6], [7]. Though they might have succeeded in increasing the potency or hardiness of a fungus specie, they did not take a step further to consider that the evaluation the fungal insecticide must follow before commercialization, which includes the assessment of its toxicity towards humans and animals, dispersal, horizontal gene transfer rate, and its effects on the resident microflora [5].


Our Solution



The lack of biosafety development for genetically engineered fungal insecticides hinders its commercialization and public acceptance. To address this problem, we, 2016 NYMU_Taipei, have designed a light-induced kill switch aimed to reduce the dispersal and horizontal gene transfer of genetically engineered fungal insecticides. Using an entomopathogenic fungus, Metarhizium anisopliae, that is applied as an insecticide around the world as our chassis, we have constructed a genetically modified M. anisopliae with wildtype lethality and the additional ability to self-terminate after killing its host.

Reference



1. Mallet J. The evolution of insecticide resistance: have the insects won? Trends Ecol Evol.1989;4(11):336–40. doi: 10.1016/0169-5347(89)90088-8.

2. Zhu, F., Lavine, L., O’Neal, S., Lavine, M., Foss, C., & Walsh, D. (2016). Insecticide Resistance and Management Strategies in Urban Ecosystems.Insects, 7(1), 2.

3. Reid, M. C., & McKenzie, F. E. (2016). The contribution of agricultural insecticide use to increasing insecticide resistance in African malaria vectors. Malaria Journal, 15, 107. http://doi.org/10.1186/s12936-016-1162-4

4. Sudakin D.L. Biopesticides. Toxicol. Rev. 2003;22:83–90.

5. Bonaterra, A., Badosa, E., Cabrefiga, J., Francés, J., & Montesinos, E. (2012). Prospects and limitations of microbial pesticides for control of bacterial and fungal pomefruit tree diseases. Trees (Berlin, Germany : West), 26(1), 215–226.

6. St Leger, R., Joshi, L., Bidochka, M. J., & Roberts, D. W. (1996). Construction of an improved mycoinsecticide overexpressing a toxic protease. Proceedings of the National Academy of Sciences of the United States of America, 93(13), 6349–6354.

7. Wang CS, St Leger RJ (2007) A scorpion neurotoxin increases the potency of a fungal insecticide. Nat Biotechnol 25: 1455–1456.

8. Wang, C., & St. Leger, R. J. (2006). A collagenous protective coat enablesMetarhizium anisopliae to evade insect immune responses. Proceedings of the National Academy of Sciences of the United States of America, 103(17), 6647–6652.