Progress 05/25/03 to 05/24/05
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Provide basic insect molecular genetic data by 1)designing and developing methods to identify adult/immature insects; 2)establishing relationships among species, populations, and biotypes; 3)inferring possible geographic origins; 4)creating a reservoir of molecular genetic markers. This genetic foundation will be available to the agricultural research community and also provide support to government action agencies and special problems. A. Evidence exists that corn rootworms are adapting to many current control practices. Insecticide resistance, extended diapause, changes in host plant and other phenotypes all pose a threat to both current control technologies and future technologies that could reduce pesticide use. These new problems are superimposed on our lack of fundamental knowledge of genetic
factors such as gene flow, geographic distribution of genetic variability, and relationships of species/subspecies. This knowledge gap hampers our ability to address control problems in a systematic fashion not only in corn rootworm but other pests (e.g. Lygus) as well. DNA technology will be used to survey population variability and estimate the extent of gene flow (i.e. movement) among populations. DNA markers will be recovered that discriminate immature species to assist molecular biosystematics and support research on the natural distribution and competition among the juveniles. Conduct a search for molecular markers associated with the emerging problem phenotypes. B. USDA has been attempting to expand the use of biological control (BC) to help reduce/eliminate the use of synthetic pesticides. The possible existence of unrecognized cryptic taxa (biotypes, subspecies and sibling species, etc.) within target pests or their parasitoids and predators poses a threat to the success of
biological control. Lack of suitable methods to identify which of the several geographic strains released have established themselves in the field makes selection of effective BC organisms almost impossible. Special reference is directed to exotic imports and their endemic counterparts. One group under investigation is the Aphthona flea beetle complex that has been imported to help control leafy spurge. C. Lygus bugs comprising several species do damage to a wide range of crops in North America. Species recognition is difficult and there is little data addressing issues such as whether the same species on cotton in the Southwest or sugar beets in the Northern Plains represent genetically distinct geographic or host range populations. Commercial sunflowers have both an assortment of pests and an assortment of parasitoids and predators of these pests. Develop DNA-based methods to identify and monitor the movements and ascertain the genetic variation of the sunflower pest insect complex
(sunflower beetle, red and gray seed weevils, stem weevil, sunflower head moth, and banded sunflower moth) and the parasitoids and predators of these insects that are being evaluated for their BC potential. D. Use DNA technology in response to APHIS/ARS request to investigate taxonomic status and genetic identification of boll weevils in Arizona. Attempt to ascertain whether thurberia weevils originating from wild thurberia cotton (Arizona mountains) are distinct from cotton weevils and whether the thurberia weevils pose a potential threat to cotton growing regions where the cotton weevils have been eliminated. New genetic traits threaten both current control by insecticides and also promising new procedures that could substantially reduce insecticide use. The global economy greatly increases the chances of transport of insects from their native habitat to new environments where they can become pests. In an era of profound genetic advances in crops and medicine, genetic assessment of
insects has not kept pace despite their major impact on human activities. Understanding the genetics and evolution of insect populations is essential if we are to counteract these changes, protecting both human needs and the environment. Heavy use of pesticides has resulted in the destruction of beneficial insects and other organisms that help keep pest insects in check. Annually 20 to 25 million acres of corn are treated with soil insecticides to protect the crop from corn rootworm larval feeding damage. It is the major use of soil insecticide in the United States. Foliage applied insecticides are still the front line defense for most other food and fiber crops. Reduction in the use of hazardous broad spectrum pesticides enhances the safety of the food supply and the quality of the environment which in turn benefits the health of people with fewer chemicals in the soil, in the ground water and on the crops themselves. Biological control agents have the potential to be a major factor
in protecting crops and reducing chemical use. It is extremely difficult to evaluate biological control possibilities when the parasite and sometimes even the pest cannot be reliably identified. It is up to ARS to carry out this fundamental inquiry into the genetics of insects. Other agencies, e.g. APHIS-Methods Development, also depend on ARS to provide DNA based methods for the identification of cryptic taxa, characterization of geographic and host based genetic variations (e.g. Thurberia weevils, Aphthona beetles, Lygus bugs), and monitoring the establishment and dispersal of natural enemies. 2. List the milestones (indicators of progress) from your Project Plan. Anticipated Milestones for 2005-2007: The new project plan has not yet completed the OSQR review process. In addition CRIS 5442-22000-029-00D was merged into this project in 2004. Anticipated achievements for the combined project for the next three years: Characterize the distribution and molecular genetics of Wolbachia
endosymbionts of economically important insects (e.g., Diabrotica and Aphthona). Examine nuclear genetic diversity of northern corn rootworm in association with Wolbachia infections and mtDNA population structure Determine the geographic based population diversity and phylogenetic relationships among species of the genus Lygus (tarnished plant bugs) and Aphthona flea beetles. The respiratory physiology of diapause/postdiapause sugarbeet root maggot will be characterized. Conserved sequence motifs associated with diapause specific genes in Colorado potato beetle will be determined, and their possible products (e. g. noncoding RNAs) expression patterns will be defined. Gene expression during the pre-diapause phase using the Colorado potato beetle as a model coleopteran and during diapause termination in the alfalfa leafcutting bee will be characterized. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met,
substantially met, or not met. If not met, why. 1. Determine the geographic based population diversity and phylogenetic relationships among species of Aphthona flea beetles. Milestone Substantially Met 2. The respiratory physiology of diapause/postdiapause sugarbeet root maggot will be characterized. Milestone Substantially Met 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? Replaced by new CRIS 5442-22000-39-00D, Insect Genomic Biodiversity and Molecular Regulation of Diapause. 4a What was the single most significant accomplishment this past year? Population genetics of northern corn rootworm. We found molecular genetic evidence for distinct populations of NCR. A sharp boundary between the two populations in eastern Illinois separates an eastern from a western group. Infection with different strains of the bacteria Wolbachia appears to be
responsible for the boundary. Such dramatic delineation of populations could be accompanied by phenotypic differences, such as extended diapause or resistance to transgenic corn, and cause the populations to react differently to control measures. 4b List other significant accomplishments, if any. Measured respiration rate in sugarbeet root maggot. We determined the respiration rates of the major life stages in field collected sugarbeet root maggots and maggots stored at 7 deg. C for 6 month to 5 years. Oxygen consumption was significantly lower in diapausing maggots as compared to nondiapausing maggots, pupae and adults. Respiration rates of maggots were stable during the 5 years during storage and were equivalent to that of diapausing maggots. Storage had no effect on survival or fecundity in maggots stored for 3 years; a decrease was noted in survival but not in fecundity in maggots stored for 4 years. 4d Progress report. 58-5442-2-329 This report serves to document the research
conducted under a specific cooperative agreement (58-5442-2-329) between ARS and North Dakota State University-Department of Entomology. Additional details of this research area can be found in the report for the parent CRIS 5442-22000-039-00D, "Insect Genomic Biodiversity and Molecular Regulation of Diapause." The object of this cooperative research is to characterize the molecular phylogeny and population diversity of North American insects belonging to the Lygus species complex. Lygus will be collected from the Red River Valley of North Dakota and Minnesota with additional collections to obtain Lygus from other parts of North America. Genetic diversity of Lygus within and among several known North American host habitats will be examined. In this reporting period we have obtained >100 nucleotide sequences from a portion of the mitochondrial genome containing parts of the cox1 and cox2 genes. The majority of the sequences are from Lygus lineolaris (tarnished plant bug) which is the
most widespread North American species. Samples have come from North Dakota, Minnesota, Vermont, Mississippi, Arkansas, Connecticut, Saskatchewan, Ontario and Quebec. A few examples of other species (L. borealis, L Hesperus, L. elisus, and L. keltoni) have also been sequenced. To date about 50 of the sequences have been processed in a phylogenetic analysis. These results show a rather strong similarity among most of the L lineolaris sequences from different locations. The exception to this is a fraction of the insects from New England that have a very distinct sequence. While still very preliminary, the results do not appear favorable towards finding genetically identifiable host plant strains of L lineolaris. 58-5442-2-338 This report serves to document the research conducted under a specific cooperative agreement (58-5442-2-338) between ARS and North Dakota State University-Department of Entomology. Additional details of this research area can be found in the report for the parent
CRIS 5442-22000-039-00D, "Insect Genomic Biodiversity and Molecular Regulation of Diapause." The object of this cooperative research project is to characterize the physiological and genetic characteristics involved in the ability of a pest insect, e.g. sugarbeet root maggot, in the Red River Valley of Dakota and Minnesota to overwinter and/or survive in cold storage. Insects will be collected throughout the upper Great Plains. Respiration rates and metabolic reserves will be compared between field collected insects and those stored in the laboratory for up to 5 years. In this reporting period we determined the respiration rates of the major life stages in field collected sugarbeet root maggots and maggots stored at 7 deg. C for 6 month to 5 years. Oxygen consumption was significantly lower in diapausing maggots as compared to nondiapausing maggots, pupae and adults. Respiration rates of maggots were stable during the 5 years during storage and were equivalent to that of diapausing
maggots. The lipid reserves were quantified and major classes of lipids identified. Total lipid reserves decreased significantly after 1 year of storage. The survival rates of maggots stored at 7 deg. C for 1 to 4 years were determined. Storage had no effect on survival or fecundity in maggots stored for 3 years; a decrease was noted in survival but not in fecundity in maggots stored for 4 years. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. We found that northern corn rootworms along a previously identified genetic boundary appear to be harboring multiple Wolbachia strains in single individuals, including one or more previously undetected Wolbachia variant. The strains of the bacteria inhibit corn rootworm reproduction between individuals with different bacterial strains and have resulted in three distinct genetic populations of northern corn rootworm. This identifies a means by which corn rootworm populations can be
reproductively isolated and lead to multiple responses to control programs. Effective expansion of flea beetle populations in the biological control of leafy spurge requires a better assessment of the genetic properties of currently established populations. We examined the mitochondrial DNA of Aphthona nigriscutis flea beetles from different established sites. Two genetically distinct populations of A. nigriscutis that are isolated by the presence/absence of a Wolbachia infection were observed at all sites. The Wolbachia infected group has reduced genetic diversity and produces fewer males. This suggests that new isolates of A. nigriscutis that are free of Wolbachia may enhance the adaptability of this species to a wider variety of habitats and host plant types Internal transcribed spacers (ITS1 and ITS2) and the intergenic spacer (IGS) of the nuclear ribosomal RNA region were used to examine the genetic diversity in boll weevils. Weevils were obtained from three locations in Texas,
one location in northeastern Mexico, and three locations in southern Arizona. The Texas and Mexico samples originated from cultivated cotton while the Arizona collections were obtained from thurberia cotton, a wild relative of cultivated cotton. The boll weevil IGS is large and contains 5 histone gene sequences. We found restriction pattern differences in a portion of the IGS that differentiated between the Arizona populations from thurberia cotton and weevil populations in Texas and Mexico. Nucleotide variations in the ITS2 revealed one and two base pair differences that are indicative of three distinct weevil populations corresponding to the Texas, Mexican, and Arizonan populations. ITS1 lacked diagnostic polymorphism. The results support previous mtDNA research indicating that the Arizona thurberia" weevils are a separate population that is isolated from the cotton pest weevils. The ITS2 results combined with some previously observed rare mtDNA haplotypes provide the best evidence
so far that the Mexican boll weevil is a distinct genetic entity. This research falls under national program 304: Component I: Identification and Classification of Insects and Mites, Problem C. Systematic Studies of High Priority Pest and Beneficial Insects and Mites; Component II: Biology of Pests and Natural Enemies (Microbes), Problem A. Basic Biology; Component IX: Biological Control of Weeds, Problem A. Agent Discovery and Selection and Risk Assessment. It also relates to Stratigic Plan Goal 3: Objective 3.2, performance measure 3.2.5. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? The information on the Wolbachia-based population differentiation of the northern corn rootworm has been shared with ARS, university, and private sector scientists
working on control methods for this species and presented at national and international scientific meetings. Results of phylogenetic work with Lygus species was presented to an international gathering of Lygus researchers. At least 20 nucleotide sequences have been made available to the public via submission and inclusion in the GenBank database. Four clones of dietary regulated genes were transferred to USDA ARS Biological Control of Insects Research Laboratory, Columbia, MO. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). See CRIS 5442-22000-39-00D for all publications for FY2005.
Impacts
(N/A)
Publications
- HAMMACK, L., ELLSBURY, M.M., ROEHRDANZ, R.L., PIKUL JR, J.L. LARVAL SAMPLING AND INSTAR DETERMINATION IN FIELD POPULATIONS OF NORTHERN AND WESTERN CORN ROOTWORM (COLEOPTERA: CHRYSOMELIDAE).. JOURNAL OF ECONOMIC ENTOMOLOGY. 2003. V. 96 p. 1153-1159.
- ROEHRDANZ, R.L., SZALANSKI, A.L., LEVINE, E. MITOCHONDRIAL DNA AND ITS1 DIFFERENTIATION IN GEOGRAPHICAL POPULATIONS OF NORTHERN CORN ROOTWORM, DIABROTICA BARBERI (COLEOPTERA: CHRYSOMELIDAE): IDENTIFICATION OF DISTINCT GENETIC POPULATIONS. ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA. 2003. v. 96(6). p. 901-913.
|
Progress 10/01/03 to 09/30/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? This is a bridging CRIS that has had CRIS 5442-22000-029-00D merged into it. The combined project has not completed the OSQR process. Provide basic insect molecular genetic data by 1)designing and developing methods to identify adult/immature insects; 2)establishing relationships among species, populations, and biotypes; 3)inferring possible geographic origins; 4)creating a reservoir of molecular genetic markers. This genetic foundation will be available to the agricultural research community and also provide support to government action agencies and special problems. A. Evidence exists that corn rootworms are adapting to many current control practices. Insecticide resistance, extended diapause, changes in host plant and other phenotypes all pose a threat to both current control technologies and
future technologies that could reduce pesticide use. These new problems are superimposed on our lack of fundamental knowledge of genetic factors such as gene flow, geographic distribution of genetic variability, and relationships of species/subspecies. This knowledge gap hampers our ability to address control problems in a systematic fashion not only in corn rootworm but other pests (e.g. Lygus) as well. DNA technology will be used to survey population variability and estimate the extent of gene flow (i.e. movement) among populations. DNA markers will be recovered that discriminate immature species to assist molecular biosystematics and support research on the natural distribution and competition among the juveniles. Conduct a search for molecular markers associated with the emerging problem phenotypes. B. USDA has been attempting to expand the use of biological control (BC) to help reduce/eliminate the use of synthetic pesticides. The possible existence of unrecognized cryptic
taxa (biotypes, subspecies and sibling species, etc.) within target pests or their parasitoids and predators poses a threat to the success of biological control. Lack of suitable methods to identify which of the several geographic strains released have established themselves in the field makes selection of effective BC organisms almost impossible. Special reference is directed to exotic imports and their endemic counterparts. One group under investigation is the Aphthona flea beetle complex that has been imported to help control leafy spurge. C. Lygus bugs comprising several species do damage to a wide range of crops in North America. Species recognition is difficult and there is little data addressing issues such as whether the same species on cotton in the Southwest or sugar beets in the Northern Plains represent genetically distinct geographic or host range populations. Commercial sunflowers have both an assortment of pests and an assortment of parasitoids and predators of
these pests. Develop DNA-based methods to identify and monitor the movements and ascertain the genetic variation of the sunflower pest insect complex (sunflower beetle, red and gray seed weevils, stem weevil, sunflower head moth, and banded sunflower moth) and the parasitoids and predators of these insects that are being evaluated for their BC potential. D. Use DNA technology in response to APHIS/ARS request to investigate taxonomic status and genetic identification of boll weevils in Arizona. Attempt to ascertain whether thurberia weevils originating from wild thurberia cotton (Arizona mountains) are distinct from cotton weevils and whether the thurberia weevils pose a potential threat to cotton growing regions where the cotton weevils have been eliminated. New genetic traits threaten both current control by insecticides and also promising new procedures that could substantially reduce insecticide use. The global economy greatly increases the chances of transport of insects from
their native habitat to new environments where they can become pests. In an era of profound genetic advances in crops and medicine, genetic assessment of insects has not kept pace despite their major impact on human activities. Understanding the genetics and evolution of insect populations is essential if we are to counteract these changes, protecting both human needs and the environment. Heavy use of pesticides has resulted in the destruction of beneficial insects and other organisms that help keep pest insects in check. Annually 20 to 25 million acres of corn are treated with soil insecticides to protect the crop from corn rootworm larval feeding damage. It is the major use of soil insecticide in the United States. Foliage applied insecticides are still the front line defense for most other food and fiber crops. Reduction in the use of hazardous broad spectrum pesticides enhances the safety of the food supply and the quality of the environment which in turn benefits the health
of people with fewer chemicals in the soil, in the ground water and on the crops themselves. Biological control agents have the potential to be a major factor in protecting crops and reducing chemical use. It is extremely difficult to evaluate biological control possibilities when the parasite and sometimes even the pest cannot be reliably identified. It is up to ARS to carry out this fundamental inquiry into the genetics of insects. Other agencies, e.g. APHIS-Methods Development, also depend on ARS to provide DNA based methods for the identification of cryptic taxa, characterization of geographic and host based genetic variations (e.g. Thurberia weevils, Aphthona beetles, Lygus bugs), and monitoring the establishment and dispersal of natural enemies. 2. List the milestones (indicators of progress) from your Project Plan. Objectives: Examination of genetic diversity and molecular biosystematics of Aphthona flea beetles used in leafy spurge control using mtDNA sequences and RFLPs.
Look for correlations among A. nigriscutis mtDNA haplotypes, Wolbachia infection, and distorted sex ratio. Look for correlations between Aphthona genotypes and leafy spurge biotypes that affect beetle establishment as a biocontrol agent. Determine if new strains of Aphthona beetles should be obtained to try to expand the beetles effectiveness. Molecular biosystematic and geographic polymorphism study of Lygus (tarnished plant bug). Determine if regional or host plant specific strains have developed. Examine nuclear genetic diversity of northern corn rootworm in association with Wolbachia infections. At issue is whether Wolbachia infestation leads to a reduction of nuclear genetic variability as it does for mtDNA variability. Monitor the dispersal of Wolbachia in northern corn rootworm populations to see if it is spreading to new areas and look for links to other phenotypes that might be carried along with the infection. 3. Milestones: A. This is a bridging CRIS and no formal
milestones were established for the project. The following indicates how the objectives were addressed in the past year. Look for correlations among A. nigriscutis mtDNA haplotypes, Wolbachia infection, and distorted sex ratio. Wolbachia infection has been shown to be strongly associated with one of the two groups of mtDNA haplotypes. Continue examination of genetic diversity and molecular biosystematics of Aphthona flea beetles used in leafy spurge control using mtDNA sequences and RFLPs. DNA sequences affirm the existence of at least 6 genetic clades among the four beetle species that have been established in the field. One of these groups may be a previously unrecognized species. Begin molecular biosystematic and geographic polymorphism study of Lygus (tarnished plant bug) species. RFLP and DNA sequence data of mtDNA have detected polymorphism both within and between collection sites for Lygus lineolaris. The detailed pattern of this diversity continues to be examined. Find
nuclear gene region suitable for population surveys of northern corn rootworm. A determination has been made to use microsatellites as nuclear markers in NCR. The microsatellite primers are being developed elsewhere primarily for WCR and will start to be used once the parameters have been defined. B. Anticipated Milestones for 2005-2007: The new project plan has not yet completed the OSQR review process. In addition CRIS 5442-22000-029-00D was merged into this project in 2004. Anticipated achievements for the combined project for the next three years: Characterize the distribution and molecular genetics of Wolbachia endosymbionts of economically important insects (e.g., Diabrotica and Aphthona). Examine nuclear genetic diversity of northern corn rootworm in association with Wolbachia infections and mtDNA population structure. Determine the geographic based population diversity and phylogenetic relationships among species of the genus Lygus (tarnished plant bugs) and Aphthona flea
beetles. The respiratory physiology of diapause/postdiapause sugarbeet root maggot will be characterized. Conserved sequence motifs associated with diapause specific genes in Colorado potato beetle will be determined, and their possible products (e. g. noncoding RNAs) expression patterns will be defined. Gene expression during the pre-diapause phase using the Colorado potato beetle as a model coleopteran and during diapause termination in the alfalfa leafcutting bee will be characterized. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY 2004: Effective expansion of flea beetle populations in the biological control of leafy spurge requires a better assessment of the genetic properties of currently established populations. Dr. Richard Roehrdanz, (geneticist at ARS Biosciences Research Laboratory, Fargo, ND) examined the mitochondrial DNA of Aphthona nigriscutis flea beetles from different established sites. Two
genetically distinct populations of A. nigriscutis that are isolated by the presence/absence of a Wolbachia infection were observed at all sites. The Wolbachia infected group has reduced genetic diversity and produces fewer males. This suggests that new isolates of A. nigriscutis that are free of Wolbachia may enhance the adaptability of this species to a wider variety of habitats and host plant types. B. Other Significant Accomplishment(s): Dr. Richard Roehrdanz, Biosciences Research Laboratory, Fargo, ND, found that northern corn rootworms along a previously identified genetic boundary appear to be harboring multiple Wolbachia strains in single individuals, including one or more previously undetected Wolbachia variant. The strains of the bacteria inhibit corn rootworm reproduction between individuals with different bacterial strains and have resulted in three distinct genetic populations of northern corn rootworm. This identifies a means by which corn rootworm populations can
be reproductively isolated and lead to multiple responses to control programs. C. None 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. CRIS project only 1 year old. See response to Question 4. 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? The information on the Wolbachia-based population differentiation of the northern corn rootworm has been shared with ARS, university, and private sector scientists working on control methods for this species and presented at national and international scientific meetings. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. Roehrdanz, Richard L., Sheila S. Degrugillier,
and Denise L. Olson. "Genetic diversity of introduced biological control agents: the Aphthona flea beetles and leafy spurge." Presentation at Entomological Society of America, Annual Meeting, Cincinnati, Ohio, October 26-29. 2003. Roehrdanz, R. L., "Genetics of northern corn rootworm and Wolbachia." Invited talk given at Corn Rootworm-Insecticide Resistance Management (CRW-IRM) Workshop sponsored by Monsanto Corp., St. Louis, MO, December 14-16, 2003. Roehrdanz. R. L. Gave a talk at the RRVARC customer focus group meeting titled "Using DNA to study corn rootworms and Aphthona flea beetles." December 2003. Roehrdanz, R. L. Gave talk to an expert review panel of scientists and customers titled, "Molecular genetics for insect populations, species identification and phylogeography: Insects and their DNA." October 2003. Roehrdanz, R. L. Research summary "Bacteria responsible for distinct northern corn rootworm populations" in Research New from the Valley, Red River Valley
Agricultural Research Center regionally distributed newsletter. Roehrdanz, R. L. Invited to participate in ARS Biocontrol Workshop in Greenbelt, MD in February 2004and presented: "Genetic diversity of introduced biological control agents: Aphthona flea beetles." Roehrdanz, R. L. Invited to give a talk as part of a symposium on "The Phylogeny Of The Insects - What Can Entire Mitochondrial Genome Sequence Tell Us?" at the International Entomology Congress, August 2004 in Brisbane, Australia. Presentation titled "Long PCR as a tool for detecting rearrangements of arthropod mtDNA."
Impacts
(N/A)
Publications
- HAMMACK, L., ELLSBURY, M.M., ROEHRDANZ, R.L., PIKUL JR, J.L. LARVAL SAMPLING AND INSTAR DETERMINATION IN FIELD POPULATIONS OF NORTHERN AND WESTERN CORN ROOTWORM (COLEOPTERA: CHRYSOMELIDAE).. JOURNAL OF ECONOMIC ENTOMOLOGY. 2003. V. 96 p. 1153-1159.
- ROEHRDANZ, R.L., SZALANSKI, A.L., LEVINE, E. MITOCHONDRIAL DNA AND ITS1 DIFFERENTIATION IN GEOGRAPHICAL POPULATIONS OF NORTHERN CORN ROOTWORM, DIABROTICA BARBERI (COLEOPTERA: CHRYSOMELIDAE): IDENTIFICATION OF DISTINCT GENETIC POPULATIONS. ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA. 2003. v. 96(6). p. 901-913.
|
Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? Provide basic insect molecular genetic data by 1)designing and developing methods to identify adult/immature insects; 2)establishing relationships among species, populations, and biotypes; 3)inferring possible geographic origins; 4)creating a reservoir of molecular genetic markers. This genetic foundation will be available to the agricultural research community and also provide support to government action agencies and special problems. A. Evidence exists that corn rootworms are adapting to many current control practices. Insecticide resistance, extended diapause, changes in host plant and other phenotypes all pose a threat to both current control technologies and future technologies that could reduce pesticide use. These new problems are superimposed on our lack of fundamental knowledge of genetic factors such as gene flow, geographic distribution of genetic variability, and
relationships of species/subspecies. This knowledge gap hampers our ability to address control problems in a systematic fashion not only in corn rootworm but other pests (e.g. Lygus) as well. DNA technology will be used to survey population variability and estimate the extent of gene flow (i.e. movement) among populations. DNA markers will be recovered that discriminate immature species to assist molecular biosystematics and support research on the natural distribution and competition among the juveniles. Conduct a search for molecular markers associated with the emerging problem phenotypes. B. USDA has been attempting to expand the use of biological control (BC) to help reduce/eliminate the use of synthetic pesticides. The possible existence of unrecognized cryptic taxa (biotypes, subspecies and sibling species, etc.) within target pests or their parasitoids and predators poses a threat to the success of biological control. Lack of suitable methods to identify which of the
several geographic strains released have established themselves in the field makes selection of effective BC organisms almost impossible. Special reference is directed to exotic imports and their endemic counterparts. One group under investigation is the Aphthona flea beetle complex that has been imported to help control leafy spurge. C. Lygus bugs comprising several species do damage to a wide range of crops in North America. Species recognition is difficult and there is little data addressing issues such as whether the same species on cotton in the Southwest or sugar beets, SUNFLOWER AND CANOLA in the Northern Plains represent genetically distinct geographic or host range populations. Commercial sunflowers have both an assortment of pests and an assortment of parasitoids and predators of these pests. Develop DNA- based methods to identify and monitor the movements and ascertain the genetic variation of the sunflower pest insect complex (sunflower beetle, red and gray seed
weevils, stem weevil, sunflower head moth, and banded sunflower moth) and the parasitoids and predators of these insects that are being evaluated for their BC potential. D. Use DNA technology in response to APHIS/ARS request to investigate taxonomic status and genetic identification of boll weevils in Arizona. Attempt to ascertain whether thurberia weevils originating from wild thurberia cotton (Arizona mountains) are distinct from cotton weevils and whether the thurberia weevils pose a potential threat to cotton growing regions where the cotton weevils have been eliminated. 2. How serious is the problem? Why does it matter? New genetic traits threaten both current control by insecticides and also promising new procedures that could substantially reduce insecticide use. The global economy greatly increases the chances of transport of insects from their native habitat to new environments where they can become pests. In an era of profound genetic advances in crops and medicine,
genetic assessment of insects has not kept pace despite their major impact on human activities. Understanding the genetics and evolution of insect populations is essential if we are to counteract these changes, protecting both human needs and the environment. Heavy use of pesticides has resulted in the destruction of beneficial insects and other organisms that help keep pest insects in check. Annually 20 to 25 million acres of corn are treated with soil insecticides to protect the crop from corn rootworm larval feeding damage. It is the major use of soil insecticide in the United States. Foliage applied insecticides are still the front line defense for most other food and fiber crops. Reduction in the use of hazardous broad spectrum pesticides enhances the safety of the food supply and the quality of the environment which in turn benefits the health of people with fewer chemicals in the soil, in the ground water and on the crops themselves. Biological control agents have the
potential to be a major factor in protecting crops and reducing chemical use. It is extremely difficult to evaluate biological control possibilities when the parasite and sometimes even the pest cannot be reliably identified. It is up to ARS to carry out this fundamental inquiry into the genetics of insects. Other agencies, e.g. APHIS-Methods Development, also depend on ARS to provide DNA based methods for the identification of cryptic taxa, characterization of geographic and host based genetic variations (e. g. Thurberia weevils, Aphthona beetles, Lygus bugs), and monitoring the establishment and dispersal of natural enemies. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? National Program: 304 Crop Commodity Pest Biology, Control and Quarantine, Component IV - Pest Control Technologies. This project helps fill the knowledge gap concerning genetics and movement of pests that currently limits the ability to develop
new control methods and broad- based management strategies. Molecular markers also assist the classification of species, the characterization of unique regional populations, and the development of identification methods for larval insects. 4. What were the most significant accomplishments this past year? A. Single Most Significant Accomplishment during FY 2003: Effective expansion of flea beetle populations in the biological control of leafy spurge requires a better assessment of the genetic properties of currently established populations. Dr. Richard Roehrdanz, (geneticist at ARS Biosciences Research Laboratory, Fargo, ND) in collaboration with Dr. D. Olson (entomologist at North Dakota State University) have examined the DNA of flea beetles from different established sites. DNA markers can be used for larval identification and have revealed some species to be genetically diverse while others appear to have quite limited genetic diversity. B. Other Significant
Accomplishment(s): Methods are needed to identify genetically distinct populations of insects and determine why interbreeding is limited between those populations. Dr. Richard Roehrdanz, Biosciences Research Laboratory, Fargo, ND, sequenced DNA of Wolbachia (an intracellular bacteria) from northern corn rootworms and found two very different strains of the bacteria in northern corn rootworms from different locations. The strains of the bacteria inhibit corn rootworm reproduction between individuals with different bacterial strains and have resulted in three distinct genetic populations of northern corn rootworm. This identifies a means by which corn rootworm populations can be reproductively isolated and lead to multiple responses to control programs C. Significant Accomplishments Activities that Support Special Target Populations: None. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. This is a bridging CRIS.
Previous work (CRIS 5442-22000-028-00D). DNA-based genetic markers and genetic differences separating thurberia weevils in Arizona locations (collected by ARS, AZ scientists) from Texas boll weevils (collected by ARS, TX scientists) were described that can help detect immigrants into eradicated regions. DNA sequence and RFLP data were used to infer phylogenetic relationships among five economically important Diabrotica (corn rootworm) species. Identification of three distinct populations of northern corn rootworm calls attention to the possibility that quantitative or qualitative phenotypic differences may exist between the populations that may respond differently to various control measures. DNA sequences have been obtained from a Wolbachia found in the flea beetle, Aphthona nigriscutis. The Wolbachia is believed to be the agent responsible for a preponderance of females and reduced genetic diversity in most populations of Aphthona nigriscutis that could potentially limit its
efficacy as a biological control agent FOR LEAFY SPURGE. 6. What do you expect to accomplish, year by year, over the next 3 years? Year 2004. Continue examination of genetic diversity and molecular biosystematics of Aphthona flea beetles used in leafy spurge control using mtDNA sequences and RFLPs. Look for correlations among A. nigriscutis mtDNA haplotypes, Wolbachia infection, and distorted sex ratio. Begin molecular biosystematic and geographic polymorphism study of Lygus (tarnished plant bug) species IN THE RED RIVER VALLEY OF NORTH DAKOTA AND MINNESOTA. Find nuclear gene region suitable for population surveys of northern corn rootworm. Year 2005. Continue molecular genetic studies of Aphthona beetles as needed. Expand DNA comparisons of additional corn rootworm species. Examine nuclear genetic diversity of northern corn rootworm in association with Wolbachia infections. At issue is whether Wolbachia infestation leads to a reduction of nuclear genetic variability as it does
for mtDNA variability. Continue molecular biosystematics and geographic/host plant variability of Lygus. Year 2006. Monitor the dispersal of Wolbachia in northern corn rootworm populations to see if it is spreading to new areas and look for links to other phenotypes that might be carried along with the infection. Continue molecular genetic investigation of Aphthona, as needed. Look for correlations between Aphthona genotypes and leafy spurge biotypes that affect beetle establishment as a biocontrol agent. Continue molecular biosystematics of Lygus, expanding to national or international collections. 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? New bridging CRIS. See previous CRIS (5442-22000-028-00D) 8. List your most important publications in
the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). Hammack, L., Ellsbury, M.M., Roehrdanz, R.L., Pikul, J.L. Corn Rootworm Sampling in Maize Roots and Surrounding Soil Cores. Entomological Society of America 2002 Annual Meeting November17-20, 2002 Fort Lauderdale, FL. Roehrdanz, R. L., Olson, D.L.. Mitochondrial DNA diversity in Aphthona sp. beetles and characterization of Wolbachia infection of A. nigriscutis. Entomological Society of America 2002 Annual Meeting November17-20, 2002 Fort Lauderdale, FL.
Impacts
(N/A)
Publications
- ROEHRDANZ, R.L. A MULTIPLEX POLYMERASE CHAIN REACTION METHOD FOR DIFFERENTIATING WESTERN AND NORTHERN CORN ROOTWORM LARVAE (COLEOPTERA: CHRYSOMELIDAE).. JOURNAL OF ECONOMIC ENTOMOLOGY. 96(3):669-672, 2003.
|
|