Submitted to: Biological Control
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/22/2004
Publication Date: 1/15/2005
Citation: Bai, C., Shapiro Ilan, D.I., Gaugler, R., Hopper, K.R. Stabilization of beneficial traits in heterorhabditis bacteriophora through creation of inbred lines. Biological Control. 2005. 32:220-227. Interpretive Summary: After live organisms are grown serially in the laboratory or in industrial settings, beneficial characteristics can be lost due to potentially harmful genetic changes. We used a nematode (small round worm) that is used as an environmentally friendly pesticide to demonstrate that detrimental genetic changes can be prevented by creating inbred lines (groups that are the same genetically). Adoption of our technique could lead to improved natural pest control because nematodes kept as inbred lines would be resistant to harmful genetic changes. Our results may be useful for improving the use of other natural pest control agents.
Technical Abstract: Serial culturing of organisms used for biological pest suppression often leads to detrimental genetic changes and loss of utility. We established that genetically homozygous inbred lines can deter beneficial trait decline in the entomopathogenic nematode, Heterorhabditis bacteriophora. Three inbred lines and the foundation population were serially cultured in the insect host, Galleria mellonella. Trait stability was evaluated by comparing serially cultured with non-cultured populations. Serial culture of the foundation population (16 passages) resulted in more than a 30% loss in traits deemed beneficial for biological pest suppression, i.e., virulence to an insect host (Diaprepes abbreviatus), reproductive capacity, heat tolerance (at 38 degrees C), and host-seeking ability. In contrast, the three inbred lines were impervious to decline in all beneficial traits. Our results indicate that genetic factors played an important role in trait change, and creation of inbred lines may be a useful technique for maintaining beneficial traits.