Brown marmorated stink bugs cause millions of dollars in crop losses across the United States because of the damage their saliva does to plant tissues. Researchers at Penn State have developed methods to extract the insect saliva and identify the major protein components, which could lead to new pest control approaches.
"Until now, essentially nothing was known about the composition of stink bug saliva, which is surprising given the importance of these insects as pests and the fact that their saliva is the primary cause of feeding injury to plants and crop losses," said Gary Felton, professor and head of the Department of Entomology. "Other than using synthetic pesticides, there have been few alternative approaches to controlling these pests. By identifying the major protein components of saliva, it now may be possible to target the specific factors in saliva that are essential for their feeding and, therefore, design new approaches for controlling stink bugs."
Brown marmorated stink bugs have caused millions in crop losses across the United States as a result of the damage their saliva does to plant tissues during feeding. Researchers at Penn State have developed methods for extracting the saliva of these insects and have identified the major protein components of this saliva.
Credit: Nick Sloff, Penn State
The team reported its results in today's (Feb. 26) issue of PLOS ONE.
According to Felton, stink bugs produce two types of saliva that are required for successful feeding. Watery saliva helps stink bugs to digest their food. Sheath saliva surrounds stink bugs' mouthparts and hardens to prevent spillage of sap during feeding. The hardened "sheath" remains attached to the plant when the insect is finished feeding.
"Unlike a chewing insect, which causes damage by removing plant tissue, stink bugs pierce plant tissue and suck nutrients from the plant," said Michelle Peiffer, research support assistant. "During this process, stink bugs also deposit saliva onto the plant. The interaction between this saliva and the plant is what causes the cosmetic and physiological changes that make crops unmarketable."
To extract the two types of saliva from brown marmorated stink bugs, Felton and Peiffer first collected adult bugs from homes and fields in central Pennsylvania and maintained them in their laboratory.
The researchers chilled the insects on ice. As the insects returned to room temperature, their watery saliva was secreted from the tips of their beaks. The team collected this saliva, processed it and analyzed it for protein content.
To collect sheath saliva, the scientists placed organic grape tomatoes in the cages. After two days of stink bug feeding, they removed the tomatoes from the cages and used forceps to extract the hardened sheaths from the surfaces of the tomatoes. They then processed and analyzed the sheaths for protein content.
"We found that the watery saliva and the sheath saliva have distinct protein profiles," Felton said. "In other words, we did not find any proteins in common between the two."
Consistent with a role in digestion, the team found that watery saliva contains several digestive proteins, including amylases, proteases and an esterase.
In the sheath saliva, the researchers found peroxidase, suggesting that this protein could be involved in sheath formation. In addition, they found a large number of proteins from tomato.
"These results reveal that the protein composition of the sheath is a mixture of insect- and plant-derived proteins," Felton said. "We used extraordinary precaution to avoid disrupting tomato tissues during the collection of the sheaths, so we do not believe that the composition of tomato proteins in the sheath material is a spurious artifact of our collection methods, but rather it represents the natural coalescing of insect- and plant-derived proteins that occurs during formation of the sheath and subsequent feeding. These initial findings suggest that sheath saliva may elicit a plant self-protection response."
According to the scientists, the methods they developed to extract the saliva and to analyze the proteins should be generally applicable for any species of stink bug.
In the future, the team plans to use a genetic approach to test the function of individual proteins in the saliva to determine their function and essentiality to the feeding process.
"By understanding the specific details of feeding and the damage it causes, researchers can begin to develop targeted control methods for these pests," Peiffer said.
Support for this research was provided by the U.S. Department of Agriculture's National Institute of Food and Agriculture specifically, the Coordinated Agricultural Project of the Specialty Crop Research Initiative. The Coordinated Agricultural Project includes more than 50 researchers from 10 institutions and is led by Tracy Leskey of the U.S. Department of Agriculture's Agricultural Research Service.
A'ndrea Elyse Messer | EurekAlert!
Harnessing a peptide holds promise for increasing crop yields without more fertilizer
25.11.2015 | University of Massachusetts at Amherst
Study shows how crop prices and climate variables affect yield and acreage
18.11.2015 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.
Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...
The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...
Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.
In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...
In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.
Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...
Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...
25.11.2015 | Event News
17.11.2015 | Event News
21.10.2015 | Event News
27.11.2015 | Life Sciences
27.11.2015 | Physics and Astronomy
27.11.2015 | Earth Sciences