Progress 07/01/07 to 06/30/10
Outputs
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.
Impacts
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
- 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.
- 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.
- 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.
|
Progress 07/01/07 to 06/30/09
Outputs
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 national 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 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 analysis for 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 their corresponding transgenic lines were mostly not significant and lacked biological significance. 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 clustered groups with each 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 indicate 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 from a transgenic pollen source. Average rates of gene transfer were 0.47, 0.42, and 0.13% in NC 7, Perry and Wilson, respectively. Beyond 4.5 m, gene flow occurred in a random fashion. 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. Partridge-Tylencho, Post-doctoral research associate, Virginia Tech, Tidewater AREC, Suffolk; J. Hu, Post-doctoral research associate, Virginia Tech, Tidewater AREC, Suffolk; M. Balota, Asst. Professor, Virginia Tech, Tidewater AREC, B. Shew, Associate Professor, North Carolina State Univ., Raleigh. Partnering organizations: National Peanut Board (Virginia committee); Virginia Agricultural Council. TARGET AUDIENCES: Presentations in 2007, 2008 and 2009 concerning the progress of this research and its potential value were made at the annual meetings of the American Peanut Research and Education 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: Nothing significant to report during this reporting period.
Impacts
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 has been 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 results in improved quality, yield and value. In 2007, 2008, and 2009, Sclerotinia blight appeared first in non-transformed parent cultivars and increased to moderate or high levels by harvest, whereas only low to moderate levels of Sclerotinia blight 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 disease 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 spays 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 are 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 with 5 years of data from laboratory, greenhouse and field studies in 2005 through 2009 is near completion for submission to APHIS, EPA, and FDA in 2009 or early 2010. This innovation in disease control could have saved growers in Virginia up to $1.51 million in fungicide costs on 4856 ha of peanut in 2009.
Publications
- Hu, J., Phipps, P., Partridge, D., Chriscoe, S. Grabau, E., and Shew, B. 2008. Yield and market quality of Virginia-type peanut cultivars engineered with the oxalate oxidase gene for resistance to Sclerotinia blight. Proc. Amer. Peanut Res. and Educ. Soc. 40:(in press).
- Hu, J., Phipps, P., and Grabau, E. 2009. Response of Virginia-type peanuts with a barley oxalate oxidase gene to Sclerotinia blight, 2008. Plant Dis. Mgt. Rep. 3:FC005.
- Hu, J., Phipps, P., Chriscoe, S., Grabau, E., and Shew, B. 2009. Response of Virginia-type peanuts with a barley oxalate oxidase gene to Sclerotinia blight, 2008. Plant Dis. Mgt. Rep. 3:FC004.
- Hu, J., Phipps, P., Partridge, D., and Grabau, E. 2009. Assessment of similarities between non-transgenic and transgenic peanut with resistance to Sclerotinia blight. Proc. Amer. Peanut Res. & Educ. Soc. 41:(in press).
- Hu, J., Phipps, P., and Grabau, E. 2009. Field evaluation of virginia-type peanuts transformed with a barley oxalate oxidase gene for resistance to Sclerotinia blight. Phytopathology 99:S55.
|
Progress 07/01/07 to 06/30/08
Outputs
OUTPUTS: This project seeks to gather the documentation required for petitioning government agencies for deregulation and release of transgenic lines of peanut containing an oxalate oxidase gene from barley. In five years of field testing, transgenic lines with the gene have exhibited high levels of resistance to Sclerotinia blight and produced an excellent yield of high quality Virginia-type peanuts. Transgenic lines were tested in 2007 and 2008 for agronomic traits, resistance to Sclerotinia blight and resistance/susceptibility to other diseases at the Tidewater AREC in Suffolk (VA) and the Upper Coastal Plain Research Station in Rocky Mount (NC). Included were transformed lines of the cultivars Perry, Wilson and NC 7. Superior selections of transformed lines have been advanced through the T6 and T8 generations with screens for heritability of traits, expression of oxalate oxidase, and disease resistance in each generation. Southern blot assays were used to examine transformed lines for the number of gene insertions, numbers of copies at insertion loci, gene stability through generations, intactness of the plasmid backbone and expression cassettes, and the approximate point of recombination at each insertion. Field trials of transgenic lines from 2005 through 2008 are providing data to petition for deregulation and release of transgenic lines. Tests have included assessments of hay quality, pod size and brightness, market grade characteristics, and market value according to USDA standards. Kernel chemistry has included an analysis for iodine value (shelf life), levels of 10 fatty acids including the oleic and linoleic ratio, mineral content (Ca, K, P, S, Mg), and blanching efficiency. Additional studies have defined the frequency and distance of outcrossing between transgenic and nontransgenic lines, risk for transgenic lines becoming weeds, and impact of transgenic lines on aflatoxin incidence in kernels. PARTICIPANTS: Dr. J. Hu, Post-doctoral Research Associate, Virginia Tech, Tidewater AREC, Suffolk; B. Keeling, Research Specialist Sr., Virginia Tech, Tidewater AREC, Suffolk; R. Byrum, Agricultural Research Manager, Virginia Tech, Tidewater AREC, Suffolk; Dr. B. Shew, Associate Professor, North Carolina State Univ., Raleigh; National Peanut Board - Virginia committee; Virginia Agricultural Council TARGET AUDIENCES: Presentations concerning the progress of this research and its potential value were made at the Annual Meeting of the American Peanut Research and Education Society in 2007 and 2008; growers and extension agents at the 2007 and 2008 Pre-harvest Tours at the Tidewater AREC in Suffolk, VA; research and industry professionals attending the 2007 and 2008 Tour of Applied Research on Field Crop Disease Control in September at the Tidewater AREC in Suffolk, VA; the Board of Directors of the North Carolina Peanut Growers Assoc. in 2007; the Virginia-North Carolina Peanut Advisory Committee in 2007; and meetings of the Board of Directors of the Virginia Peanut Growers Assoc. in 2007 and 2008. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
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 has been shown to be specific for Sclerotinia blight and not against other diseases such as early and late leaf spot, web blotch, tomato spotted wilt virus, or Cylindrocladium black rot. The primary benefit of the oxalate oxidase gene in Virginia-type peanut cultivars has been high levels of resistance to Sclerotinia blight which results in improved quality, yield and value. In 2007 and 2008, Sclerotinia blight appeared first in non-transformed parent cultivars and increased to moderate or high levels by harvest, whereas only a trace to low levels of Sclerotinia blight were present in transformed lines with the oxalate oxidase gene at harvest. According to area under the disease progress curve (AUDPC), six advanced-generation transgenic lines had an average of 97% less disease than their non-transformed parent in 2007 field trials and evaluations of transgenic lines in 2008 are producing similar results. Yields of transgenic lines were either similar or significantly greater compared to their non-transformed parent in 2007. Grade, blanching and nutrient characteristics after harvest showed that transformed lines of Perry and Wilson had significantly increased percentages of fancy pods and the transformed line of NC 7 had significantly increased percentages of jumbo pods. Transgenic lines of Perry, Wilson and NC 7 produced increased values ranging from $72 to 297/ha based on grade characteristics and value at the government loan rate. While no changes were seen in levels of Ca, K, and S in kernels from transgenic lines, levels of Mg were higher than in their non-transformed parents. Levels of P were increased significantly in a transformed line of Perry, whereas no significant differences were observed in other transgenic lines compared to their non-transformed parent. Aflatoxin levels in all transgenic lines and non-transgenic parental controls were below the allowed market standard of 20 ppb for edible trade and below the detection limit (5 ppb) of the assay method in 2007. Gene flow through natural outcrossing of transgenic and non-transgenic plants was evaluated in 2007 by seed embryo assays of harvested peanut kernels. A colorimetric measure of hydrogen peroxide released from an oxalic acid substrate was used to detect gene flow. The out-crossing rate was 1.1% at 1.8 m (two rows) away from transformed lines of Wilson and Perry, while NC 7 showed an out-crossing rate of 1.4% at 1.8 m away from its transformed lines. Outcrossing decreased to undetectable levels at 3.8 m away from transformed lines of Wilson and Perry, while outcrossing was detected up to 17.4 m (17 rows) away from transformed lines of NC 7. Bumble bees were the primary insect observed collecting pollen from peanut flowers in the 2007 field trial.
Publications
- Chriscoe, S., Grabau, E., Partridge, D., and Phipps, P. 2007. Navigating the governmental approval process for release of transgenic peanuts with enhanced resistance to Sclerotinia blight. Proc. Amer. Peanut Res. and Educ. Soc. 39:48-49.
- Partridge, D., Phipps, P., Criscoe, S., and Grabau, E. 2007. Field assessment of Virginia-type peanuts transformed with the oxalate oxidase gene in 2006. Proc. Amer. Peanut Res. and Educ. Soc. 39:52-53.
- Hu, J., Phipps, P., Chriscoe, S., Grabau, E., and Shew, B. 2008. Response of Virginia-type peanuts with a barley oxalate oxidase gene to Sclerotinia blight, 2007. Plant Dis. Mgt. Rep. 2:FC093.
- Hu, J., Phipps, P., Chriscoe, S., and Grabau, E. 2008. Disease susceptibility in Virginia-type peanuts transformed with a barley oxalate oxidase gene, 2007. Plant Dis. Mgt. Rep. 2:FC094.
- Hu, J., Phipps, P., Partridge, D., Chriscoe, S. Grabau, E., and Shew, B. 2008. Yield and market quality of Virginia-type peanut cultivars engineered with the oxalate oxidase gene for resistance to Sclerotinia blight. Proc. Amer. Peanut Res. and Educ. Soc. 40:(in press).
- Hu, J., Phipps, P., Chriscoe, S., Grabau, E. 2008. Measuring gene flow from transgenic peanuts to nontransgenics in the same field. Phytopathology 98:S215.
|
|