2017 SMRT Grant Finalist
Unravelling the Mysteries of the Explosive Bombardier Beetle
Dr. Tanya Renner, San Diego State University
Dr. Aman Gill, University of California, Berkeley
Dr. Wendy Moore, University of Arizona
Dr. Kipling Will, University of California, Berkeley
Dr. Athula Attygalle, Stevens Institute of Technology
About This Project
Although powerful chemical weapons are rare in the animal world, some insects use them to protect themselves against their enemies. Bombardier beetles (Brachinus elongatulus) have taken this to an extreme. They explosively blast boiling hot, noxious chemicals from their abdomen at their predators. We propose to sequence the bombardier beetle genome to learn how this remarkable beetle makes these toxic chemicals, stores them within its body, and discharges them without self-injury.
Why is this the most interesting genome in the world?
Bombardiers are among the world’s most impressive chemists. Unlike pheromones used for communication, their genetic machinery provides for biochemical warfare. They repel predators with rapid-fire, precisely-aimed explosive discharges of a toxic chemical mix at over 100°C, earning them lead roles in media and culture. Yet the genomic basis of this extraordinary ability remains a mystery. The first bombardier genome will allow us to understand the genetic basis of bombardier chemical production, solving a long-standing evolutionary puzzle. This understanding will elucidate the currently unknown genetic basis of explosive chemical defense in the animal kingdom.
What are the goals of this project?
Our goal is to assemble the complete genome of the bombardier beetle, Brachinus elongatulus, using PacBio’s SMRT Sequencing technology. A Brachinus genome (~500 Mb) will accelerate our ongoing National Science Foundation-funded research, helping us to resolve the genetic basis of carabid beetle chemical defense. We are currently using comparative transcriptomics to identify the genes and biochemical pathways involved in the production of defensive chemicals. The complete genome will elevate this research by i) revealing the genomic architecture of biosynthesis genes and the regulatory factors controlling their expression, ii) allowing us to pinpoint or exclude biosynthetic roles played by microbes or horizontal gene transfer events, iii) enabling comparative studies into the immense diversity of biosynthetic pathways in other ground beetle species.
What is the global impact of your research?
The Brachinus genome will be used by many researchers, as it will be the first genome from a major branch of the tree of life, the beetle suborder Adephaga, providing a unique point of comparison to other insects and to the few existing beetle genomes, which are all from other suborders. We will use it to provide a framework for understanding the genetic basis of defensive chemical systems and a new foundation for research in chemical biosynthesis. Our genome-based findings of the bombardier beetle will provide a solid evidence-based explanation for their remarkable defensive strategy, shedding light on a mystery that has given rise to extensive speculation but few solid answers, thus making bombardier beetles a valuable and powerful evolutionary case study for the classroom.
Project Team (in addition to PIs)
- Reilly McManus, University of Arizona
- Dr. Thomas Eisner (in memoriam, 1929 – 2011)
Watch the Bombardier beetle’s “chemical cannon” in action