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Funded Project |
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Funding Program:
Regional IPM Grants (S-RIPM) |
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Project Title:
Enhancing IPM programs through deregulation and release of genetically modified Virginia-type peanuts with resistance to Sclerotinia blight |
Project Directors (PDs):
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Lead State: VA Lead Organization: Virginia Polytechnic Institute and State University |
| Research Funding: $119,998 |
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Start Date: Mar-01-2007 End Date: Feb-28-2009 |
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Pests Involved: Sclerotinia Blight |
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Site/Commodity: Peanuts |
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Summary:
This is a Research project requesting $119,998 funds to cover research on characterization of disease resistance, marketability, deregulation and commercial release of genetically modified Virginia-type peanuts in the mid-Atlantic region in 2007 and 2008. Sclerotinia blight is one of the most important diseases of peanut in the Virginia and North Carolina production region. Peanut growers in this region have the highest production costs in the United States, because of the crops requirement for supplemental calcium and intensive use of chemicals for disease control. Fungicides for control of Sclerotinia blight can cost growers as much as $74 to $111 per acre. If left untreated, Sclerotinia blight can reduce yields up to 75% in heavily infested fields. Development of disease resistant peanut varieties would provide an alternative management option to farmers that would help restore the planting of peanut in IPM programs aimed at reducing populations of southern root knot nematode, reniform nematode, and soybean cyst nematode in crop rotations with soybean, corn, and cotton.
The production of oxalic acid has been recognized as a pathogenicity factor for fungal pathogens such as Sclerotinia minor, the causal agent of Sclerotinia blight. To counteract the effects of oxalic acid and to reduce the dependency on expensive fungicide treatments, we introduced the barley oxalate oxidase gene into three Virginia-type peanut cultivars; NC 7, Wilson, and Perry. Field trials have evaluated the second, third, and fourth generations of genetically transformed lines and confirmed gene expression in each generation. Low to only trace levels of disease were detected in field evaluations of genetically transformed lines, whereas in all three years disease appeared first in the non-transformed parent cultivars and reached severe levels. Replicated trials in 2005 and 2006 showed that early generations of genetically transformed lines had an average of 81% less disease than their non-transformed parent with increases in yield up to 2200 lb/A. Laboratory tests confirmed the heritability and functionality of the oxalate oxidase gene in providing resistance against Sclerotinia blight. The specific objectives of this project are to: 1) characterize the performance of advanced generations of genetically transformed lines with the barley oxalate oxidase gene and their non-transformed parents in fields at experiment stations in Virginia (Tidewater) and North Carolina (Lewiston) over a two-year period with and without applications of fluazinam for control of Sclerotinia blight, 2) collect required field, greenhouse, and laboratory data needed to successfully petition for deregulated status from Animal and Plant Health Inspection Service (APHIS) so that disease resistant lines containing the oxalate oxidase gene can be deregulated, and 3) gain approval of the Environmental Protection Agency (EPA) for commercial release of superior transgenic lines. EPA jurisdiction of this request is a result of oxalate oxidase being a crop protectant that is found naturally in other food crops. Its mode of action is through prevention of fungal colonization of plant cells rather than acting as a toxic agent that kills the invading organism.
This proposal has broad stakeholder input and support from the peanut industry including the two state commodity boards (Virginia and North Carolina), the Virginia Agricultural Council, and the National Peanut Board. Research findings are expected to have an impact on the industry by providing an alternative IPM management option to farmers once deregulated status is achieved.
Objectives: The specific objectives are to: 1) characterize the performance of advanced generations of genetically transformed lines with the barley oxalate oxidase gene and their nontransformed parents in fields at experiment stations in Virginia (Tidewater) and North Carolina (Lewiston) over a two-year period with and without applications of fluazinam for control of Sclerotinia blight, 2) collect required field, greenhouse, and laboratory data needed to successfully petition for deregulated status from Animal and Plant Health Inspection Service (APHIS) so that disease resistant lines containing the oxalate oxidase gene can be deregulated, and 3) gain approval of the Environmental Protection Agency (EPA) for commercial release of superior transgenic lines. |
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Final Report: |
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Results From report submitted by the PI to USDA CRIS report system PROGRESS: 2007/07 TO 2010/06 OUTPUTS: The goal of this project was to complete documentation required to petition government agencies for deregulation and release of transgenic lines of peanut with an oxalate oxidase gene from barley. Results of research were published annually in professional reports, popular-style articles and extension publications. Events included training sessions for extension agents, research updates at state and regional meetings, and presentations at area-wide field tours and professional meetings. Transgenic lines and their non-transformed parents were evaluated at the Tidewater Agricultural Research and Extension Center in Suffolk (VA) and the Upper Coastal Plain Research Station in Rocky Mount (NC). Included were transformed lines with barley oxalate oxidase and their non-transformed parents (Perry, Wilson and NC 7). Annual trials in naturally-infested fields demonstrated that transgenic lines were highly resistant to Sclerotinia blight and peanut yields were consistently superior to that of their non-transformed parents. Additional comparisons included assessments of hay quality, pod size and brightness, grade characteristics, and market value according to USDA standards. Kernel chemistry included iodine value (shelf life), fatty acids, oleic and linoleic ratio (O/L), polyunsaturated/saturated ratio (P/S), mineral content (Ca, K, P, S, Mg), aflatoxin, blanching efficiency, and food label data. Comparisons of differences between parent cultivars and corresponding transgenic lines were mostly not significant or were associated with increased disease in non-transgenic parent cultivars. In addition, multivariate data were analyzed by a canonical discriminate analysis. The first three canonical functions were significant at P=.0001 and accounted for more than 92% of cultivar variation. O/L, P/S, iodine value, percentages of fancy pods and extra large kernels were the most differentiating traits. These traits separated the cultivars into three, distinct clusters containing the parent cultivar and its transgenic lines. The three clusters were significantly different based on the pairwise Mahalanobis distance (P=0.01), but there were no significant differences between transformed lines and their corresponding parent. Overall, data indicated that transformation with oxalate oxidase was specific for Sclerotinia blight and not other diseases or pests. Transformation of a peanut cultivar with oxalate oxidase did not result in significant changes in kernel or hay chemistry, and did not increase the risk of aflatoxin in kernels. Field studies defined the frequency and distance of outcrossing between transgenic and nontransgenic lines. The greatest potential for outcrossing and gene flow between non-transgenic and transgenic lines occurred within 4.5 m of a transgenic pollen source. Average rates of gene transfer were 0.47, 0.42, and 0.13% in NC 7, Perry and Wilson, respectively. The maximum distance for detection of an outcrossing event was 17.1 m in field trials conducted in 2007 and 2008. Field observations indicated that bumble bees were most likely responsible for cross pollination of peanut flowers and gene flow. PARTICIPANTS: Individuals who worked on project: D. E. P. Telenko, Research Scientist, Virginia Tech, Tidewater AREC, Suffolk; J. Hu, Post-doctoral Research Associate, Univ. of Florida, Gainesville; M. Hunt, Post-doctoral Research Associate, Virginia Tech, Blacksburg; B. Shew, Associate Professor, NC State Univ., Raleigh; M. Balota, Assistant Professor, Virginia Tech, Tidewater AREC, Suffolk. Partnering organizations: National Peanut Board (Virginia Committee); Virginia Agricultural Council; USDA, Southern Region IPM Program. TARGET AUDIENCES: Presentations in 2007, 2008, 2009 and 2010 concerning the progress of this research and its value were made at annual meetings of the American Peanut Research and Education Society and the American Phytopathological Society; meetings and annual tours of growers and extension agents in Virginia; research and industry professionals; meetings of the Board of Directors of the North Carolina Peanut Growers Assoc. in 2007; meetings of the Virginia-North Carolina Peanut Advisory Committee; and meetings of the Board of Directors of the Virginia Peanut Growers Assoc. PROJECT MODIFICATIONS: Project was extended for one year (7/1/2009 - 6/30/2010) for completion of DNA analysis in transgenic lines and submission of petition to APHIS for deregulation of lines with oxalate oxidase gene from barley. IMPACT: 2007/07 TO 2010/06 Sclerotinia blight is a highly destructive disease that causes devastating losses of peanut yield in Virginia and northeastern North Carolina. Results of this project have shown that transgenic lines have agronomic and quality traits that are identical to their non-transformed parents. Disease resistance was shown to be specifically against Sclerotinia blight and not against other diseases such as early and late leaf spot, web blotch, tomato spotted wilt virus, southern stem rot, or Cylindrocladium black rot. The primary effect of the oxalate oxidase gene on Virginia-type peanut cultivars was high levels of resistance to Sclerotinia blight which resulted in improved quality, yield and value. In 2007, 2008, and 2009, Sclerotinia blight appeared first in non-transformed parent cultivars and reached moderate to high levels by harvest, whereas only low to moderate levels were present in transformed lines with the oxalate oxidase gene at harvest. According to area under the disease progress curve (AUDPC), six transgenic lines had an average of 97% less Sclerotinia blight than their non-transformed parent in field trials. Yields of transgenic lines were either similar or significantly greater compared to their non-transformed parents. Transgenic lines of Perry, Wilson and NC 7 produced increased values ranging from $72 to 297/ha based on yield, grade characteristics and value at the government loan rate. Currently, the only approved control for Sclerotinia blight of peanut is to apply one to three sprays of the fungicide fluazinam (Omega 500) at a cost of $87/ha for each application. In most years, growers have needed two or three applications for disease control which were no more effective than disease control provided by transgenic lines with the oxalate oxidase gene. A petition for deregulation and release of superior transgenic lines was submitted to APHIS in March 2010 and we are currently revising and adding information to the document as requested by APHIS. Similar requests will be prepared for submission to EPA and FDA in 2011. Upon approval for release, this innovation in disease control has the potential to save peanut growers in Virginia up to $1.51 million annually in fungicide costs on 4856 ha of peanut PUBLICATIONS (not previously reported): 2007/07 TO 2010/06 1. Chriscoe, S. M., Hu, J., Partridge, D. E., Phipps, P. M., and Grabau, E. A. 2008. Outcrossing in Virginia-type peanut cultivars (NC7, Perry and Wilson) using the transgene oxalate oxidase as a marker. Proc Amer. Peanut Res and Educ. Soc. 40:61-62. 2. Grabau, E., Hu, J., Phipps, P. M., 2009. Evaluation of Virginia-type peanuts engineered with a barley oxalate oxidase gene to petition for deregulated status. Proc. Amer. Peanut Res. & Educ. Soc 41:55. 3. Phipps, P. M., Hu, J., and Grabau, E. A., 2010. Response of Virginia-type peanuts with a barley oxalate oxidase gene to Sclerotinia blight, 2009. Plant Dis. Mgt. Rep. 4:FC033. |
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Outcomes N/A |
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Impacts From report submitted by the PI to USDA CRIS report system Sclerotinia blight is a highly destructive disease that causes devastating losses of peanut yield in Virginia and northeastern North Carolina. Results of this project have shown that transgenic lines have agronomic and quality traits that are identical to their non-transformed parents. Disease resistance was shown to be specifically against Sclerotinia blight and not against other diseases such as early and late leaf spot, web blotch, tomato spotted wilt virus, southern stem rot, or Cylindrocladium black rot. The primary effect of the oxalate oxidase gene on Virginia-type peanut cultivars was high levels of resistance to Sclerotinia blight which resulted in improved quality, yield and value. In 2007, 2008, and 2009, Sclerotinia blight appeared first in non-transformed parent cultivars and reached moderate to high levels by harvest, whereas only low to moderate levels were present in transformed lines with the oxalate oxidase gene at harvest. According to area under the disease progress curve (AUDPC), six transgenic lines had an average of 97% less Sclerotinia blight than their non-transformed parent in field trials. Yields of transgenic lines were either similar or significantly greater compared to their non-transformed parents. Transgenic lines of Perry, Wilson and NC 7 produced increased values ranging from $72 to 297/ha based on yield, grade characteristics and value at the government loan rate. Currently, the only approved control for Sclerotinia blight of peanut is to apply one to three sprays of the fungicide fluazinam (Omega 500) at a cost of $87/ha for each application. In most years, growers have needed two or three applications for disease control which were no more effective than disease control provided by transgenic lines with the oxalate oxidase gene. A petition for deregulation and release of superior transgenic lines was submitted to APHIS in March 2010 and we are currently revising and adding information to the document as requested by APHIS. Similar requests will be prepared for submission to EPA and FDA in 2011. Upon approval for release, this innovation in disease control has the potential to save peanut growers in Virginia up to $1.51 million annually in fungicide costs on 4856 ha of peanut |
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