2008 Annual Report
1a.Objectives (from AD-416)
Make publicly available a predictive computer program for mycotoxin levels in Midwest corn and adapt as necessary for a wider range of human food use corn varieties. Use molecular biological approaches to discover, introduce, and evaluate new insect resistance genes (producing bioactive proteins and secondary metabolites), alone and in combination. Use molecular biological approaches to discover, introduce, and evaluate plant-derived selectable markers for transgenic plant production.
1b.Approach (from AD-416)
As part of the process of making the program publicly available, feedback on the present state of the program will be sought and utilized as appropriate. An electronic module to assist in making control decisions will be developed and incorporated. The program will be tested for utility in food grade corn by comparing actual field collected data with predicted levels and correcting as necessary empirically. Genes identified in the prior project that are potentially useful in combination will be examined in model systems and further evaluated. New genes of potential use will be identified through functional targeting of cDNA, array-based technology. Molecular evolution of genes coding for resistance proteins will be utilized to further optimize efficacy against insects, while at the same time minimizing vertebrate effects. Gene product efficacy will be examined in model systems and in regenerated corn. Plant-derived genes involved in toxin resistance will be the ultimate focus of the investigation, although genes from other sources will initially be examined if appropriate plant-derived gene sequence information is not yet sufficient for cloning. Efficacy of target gene products as selectable markers and against insects, alone and in combination with insect-active genes, will be investigated.
Additional data was collected for validation of the mycotoxin predictive computer program, including from several popcorn fields. The predictive mycotoxin program for Midwest corn was put on a password entry governed, publically accessible website. A companion economic decision-making module was written for use with the predictive program. Active extracts from petunia, palm, and sedge were further subfractionated. The first batch of corn plants expressing a new version of a gene that could lead to production of an insecticidal novel secondary metabolite in corn were evaluated. Additional plants containing a multigene combination for insect control were transformed, and some were evaluated for activity. Two new genes potentially involved in insect/disease resistance in corn were cloned. A submitted invention disclosure may benefit corn growers, grain buyers, feed-lot managers, and grain exporters. Two complete gene sequences for potential pest resistance genes in switchgrass were identified. An invention disclosure submitted may benefit land-use managers, biomass-to-ethanol industry, and plant breeders. This research addresses NP 108, Component 2.
CORN-DERIVED GENE USEFUL AS SELECTABLE MARKER. Insect damage and associated ear-mold toxins cause hundreds of millions of dollars in losses each year. Introduction of genes coding for insecticidal compounds can help reduce insect damage, but current selectable markers in use can deter acceptability of transformed material by consumers, and thus limit the application of this technology for reduction of mycotoxins. A gene was cloned from a unique line of corn and found to be useful as a selectible marker when introduced into lines that did not contain the gene. This gene also significantly increased insect resistance when introduced into corn. Use of this gene can potentially enhance acceptability and insect resistance of corn engineered for enhanced insect or disease resistance using additional genes, thereby reducing ear mold toxins, improving the health of animals and people, and increasing the exportability of U.S. corn. This research addresses NP 108, Component 2, Problem Statement 2.1.2.
MOLECULAR EVOLUTIONARY ROBOTICS USED TO DEVELOP MORE INSECTICIDAL PEPTIDES. Insect damage and associated ear-mold toxins cause hundreds of millions of dollars in losses each year. Agricultural Research Service scientists, university, and industry collaborators utilized co-developed technology to produce more insecticidal peptides. This methodology is potentially useful in improving the activity and selectivity of pesticidal proteins and other bioactive proteins. Reduction of populations of insect pests that damage corn ears can also reduce ear mold toxins, improve the health of animals and people, and increase the exportability of United States corn. This research addresses NP 108, Component 2, Problem Statement 2.1.2.
5.Significant Activities that Support Special Target Populations
A predictive computer program was used as part of an ear mold toxin (mycotoxin) management program with a 200-farmer organization again which provided useful predictions of fumonisin and aflatoxin levels for corn (including popcorn) in 2007. Values predicted were close to those actually encountered. Once made widely available, this computer program should allow farmers to more economically produce larger amounts of healthier, high-quality corn with reduced levels of mycotoxins. This higher-quality product should help the farmers increase sales and help livestock productivity of farmers using corn for on-farm animal feed.
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Johnson, E.T., Berhow, M.A., Dowd, P.F. 2008. Colored and white sectors from star-patterned Petunia flowers display differential resistance to corn earworm and cabbage looper larvae. Journal of Chemical Ecology. 34:757-765. DOI: 10.1007/s10886-008-9444-0
Hughes, S.R., Dowd, P.F., Hector, R.E., Riedmuller, S.B., Bartolett, S., Mertens, J.A., Qureshi, N., Liu, S., Bischoff, K.M., Li, X., Jackson Jr, J.S., Sterner, D., Panavas, T., Cotta, M.A., Farrelly, P.J., Butt, T. 2007. High-throughput fully automated construction of a multiplex library of mutagenized open reading frames for an insecticidal peptide using a plasmid-based functional proteomic robotic workcell with improved vacuum system. Journal of Laboratory Automation. 12(4):202-212.