WEST LAFAYETTE, Ind. - A team of international researchers has sequenced the genome of the Nevada dampwood termite, providing an inside look into the biology of the social insect and uncovering new genetic targets for pest control.
Michael Scharf, a Purdue University professor of entomology who participated in the collaborative study, said the genome could help researchers develop control strategies that are more specific than the broad-spectrum chemicals conventionally used to treat termite infestations.
"The termite genome reveals many unique genetic targets that can be disrupted for better termite control," said Scharf, who is the O. Wayne Rollins/Orkin Chair in Molecular Physiology and Urban Entomology. "Depending on which gene or protein that is targeted, we could disrupt termites' neurological processes, molting, digestive factors or cuticle formation. We're just limited by our imagination."
The Nevada dampwood termite is the first termite species to have its genome sequenced. While dampwood termites do not cause significant damage to buildings, they are closely related to key pests such as the eastern subterranean termite, which is the main pest species in Indiana and the eastern U.S.
Termites are major pests of human structures, costing an estimated $40 billion in damage and control treatment each year. Having the genome in hand will enable researchers to look for common features expressed across termite species to find control targets effective for all types of termites, Scharf said.
Current termite control measures consist largely of synthetic chemical-based products, some of which are toxic to vertebrates.
"While current pesticides are very effective products, the problem is that you're injecting large volumes of them into the soil around the house," Scharf said. "It would be nice to move to a greener technology, and that's what the genome sequence could enable us to do."
Baiting termites with small quantities of treated wood that they could eat and share with colony-mates would be one such technique, he said. Newer technology such as gene silencing, which targets termite RNA to reduce the expression of critical genes, could also knock out the pests.
"With termites, you don't have to impact all of them," he said. "Targeting just a fraction of the workers could cause an entire colony to collapse."
The study also highlights genes related to chemical communication, the way in which termites "talk" to one another to signal aggression or a desire to reproduce.
"There's a lot of social strife in a termite colony, and it's got to stay cohesive to survive," Scharf said. "Chemical communication is crucial to keeping the labor force in place."
The genome could also help researchers better understand the symbiosis between termites and the more than 4,000 species of bacteria that thrive in their guts, aiding in processes such as digestion and defense. Previous studies of the termite gut were hampered by the inability to distinguish between termite and microbe genes. Understanding the gut biology is important to Scharf, who is researching the enzymes that termites use to digest wood. Identifying these enzymes could lead to novel methods of producing cellulosic biofuels.
"The genome provides a well-defined roadmap that could help us find the right cocktail of enzymes to break wood down into its simple sugars," he said. "It takes a lot of the guesswork out."
The study was published in Nature Communications Tuesday (May 20) and is available at http://www.
Funding for the research was provided by a grant from the U.S. Department of Agriculture's National Institute of Food and Agriculture, the Deutschen Forschungsgemeinscharf and the Loewe Research Focus "Insect Biotechnology."