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ARS Home » Southeast Area » Stoneville, Mississippi » Southern Insect Management Research » Research » Publications at this Location » Publication #388691

Research Project: Insect Control and Resistance Management in Corn, Cotton, Sorghum, Soybean, and Sweet Potato, and Alternative Approaches to Tarnished Plant Bug Control in the Southern United States

Location: Southern Insect Management Research

Title: The odorant binding protein, SiOBP5, mediates alarm pheromone olfactory recognition in the red imported fire ant, Solenopsis invicta

Author
item Chen, Jian
item Du, Yuzhe - Cathy

Submitted to: Biomolecules EISSN 2218-273X
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2021
Publication Date: 10/28/2021
Citation: Chen, J., Du, Y. 2021. The odorant binding protein, SiOBP5, mediates alarm pheromone olfactory recognition in the red imported fire ant, Solenopsis invicta. Biomolecules EISSN 2218-273X. https://doi.org/10.3390/biom11111595.
DOI: https://doi.org/10.3390/biom11111595

Interpretive Summary: The red imported fire ant is a well-known global invasive ant species. Currently, synthetic insecticides are commonly used in controlling fire ants. Traditional methods have been proven less than satisfactory for control of fire ants, leading to proposals of molecular approaches aimed at disrupting the olfactory system. Olfaction plays an important role in mediating food or mate finding and host selection behaviors of fire ants, and the odorant-binding proteins (OBPs) are involved in pheromone transportation, which are specifically expressed in the antenna. The RNA interference (RNAi) is a powerful tool that are able to partially silence some gene transcript expression. In this study, three OBP genes highly expressed in fire ant antenna, OBP1, OBP5, OBP6 were partially silenced using RNAi. RNAi SiOBP5 injected ants showed significantly lower olfactory responses to fire ants alarm pheromone. Our results indicated that SiOBP5 are crucial to fire ants for their response to alarm pheromones. RNAi knocking down SiOBP5 can significantly disrupted pheromone communication, suggesting that disrupting SiOBP5 and RNAi technique can be potentially useful in managing red imported fire ants.

Technical Abstract: Olfaction plays an important role in mediating food or mate finding and host selection behaviors of social insects, such as red imported fire ants, Solenopsis invicta Buren. Complexes of olfactory receptors (ORs) are composed of odor-specific ORs and OR co-receptors (Orco). Orcos are widely co-expressed with odor-specific ORs and are conserved across insect taxa. Odorant binding proteins (OBP), function as carrier proteins by transporting semiochemicals to ORs and thus constitute the first molecular recognition step in insect olfaction. In this study, three OBP genes highly expressed in S. invicta antenna, OBP1, OBP5, OBP6, and one Orco were partially silenced using RNA interference (RNAi). RNAi SiOBP5 and Orco injected ants showed significantly lower EAG (electroantennogram) responses to fire ants alarm pheromone and an alkaloid, 2,4,6-trimethylpyridine than water-, GFP-injected ants 72h post injection. Subsequent qRT-PCR analysis demonstrated that the transcript expression level of the OBP1, OBP5, OBP6 and Orco significantly decreased 72 h after ants were injected with dsRNAs; however, there were no transcript level and EAG changes in ants fed with dsRNAs. Our results suggested that S.invicta Orco and SiOBP5 are crucial to fire ants for their response to alarm pheromones. RNAi knocking down SiOBP5 can significantly disrupted pheromone communication, suggesting that disrupting SiOBP5 and Orco can be potentially useful in managing red imported fire ants.