Insect growth regulators (IGRs) are compounds that induce developmental anomalies such as premature molting or supernumerary larval stages. IGRs can be divided into 3 groups based on their mode of action, one of which is known as the juvenile hormone agonists (JHAs). Previously, we have developed a novel screening method which can identify juvenile hormone antagonists (JHANs) using a yeast-two hybrid system incorporating Aedes aegypti juvenile hormone receptor complex proteins (MET and FISC). It has been reported that plants may use IGRs in their defenses against insect herbivores. In this study, 171 plant essential oil samples were screened using the yeast-two hybrid system in order to identify JHAs and/or JHANs. Eight out of 171 samples, 4 JHA and 4 JHAN candidates, were selected and their insecticidal activities were investigated against A. aegypti larvae. They showed high levels of insecticidal activities, with LC50 values ranging from 11.2~21.4 ug/ml. These results indicate that plants do use JHAs and/or JHANs as a part of their defenses against insect herbivores. Also, JHAs and JHANs identified in this study could be exploited as effective biological control agents.

• Kyu Baik Ha(Department of Agricultural Biotechnology, Seoul National University)
• Seok-Hee Lee(Department of Agricultural Biotechnology, Seoul National University)
• Ying Fang(Department of Agricultural Biotechnology, Seoul National University)
• Jong Hoon Kim(Department of Agricultural Biotechnology, Seoul National University)
• Dong Hwan Par(Department of Agricultural Biotechnology, Seoul National University)
• Jae Young Choi(Research Institute for Agriculture and Life Sciences, Seoul National University)
• Woo Jin Kim(Department of Agricultural Biotechnology, Seoul National University)
• Il-Kwon Park(Department of Forest Sciences, Seoul National University)
• Yeon Ho Je(Department of Agricultural Biotechnology, Seoul National University)