Progress 07/01/06 to 05/15/08
Outputs
Progress Report Objectives (from AD-416) Characterize the structure and function of genes and their associated promoters that are required for cotton fiber development. Approach (from AD-416) Conduct functional analyses of cotton fiber genes previously isolated by differential display and other methods; use rapid methods for evaluating the efficacy/strength of cotton promoters without the need to construct transgenic cotton plants; measure minimal sizes of cis elements that specify the temporal/spatial localization patterns and hormonal induction of cotton fiber gene expression; determine if promoter structures are different for selected genes in G. hirsutum, G. barbadense, and other Gossypium species; evaluate how long gene expression proceeds during fiber development and whether there are any very late genes expressed in cotton fiber. Significant Activities that Support Special Target Populations Molecular genetic comparison of cotton plants that differ in fiber strength. Although cotton fiber strength is genetically controlled, the genes involved in producing strong fiber have not been identified. Using a method called microarray analysis to compare the activities of >21,000 cotton genes, two closely related types of cotton plants that differ in fiber strength, were analyzed. Candidate genes from this study have been validated by complementary, quantitative methods. Future work on this project will include conversion of the data into tools that can be used to breed new cotton varieties with enhanced fiber strength. Novel enzyme is localized in cotton fiber cell walls. The enzyme superoxide dismutase converts a reactive form of oxygen into the less toxic molecule, hydrogen peroxide. Using several innovative techniques to label proteins produced by model plants, we have demonstrated that the cell wall, the hard covering for each cell, contains a special form of superoxide dismutase. This protein may function in controlling fiber length and strength. Since the gene for the cell wall form of superoxide dismutase does not contain genetic information that normally specifies the final destination of this enzyme, additional study of this gene is expected to reveal new mechanisms that determine how proteins are directed to the surface of plant cells. This line of genomic investigation is expected to contribute to new strategies for modifying cotton fiber structure and properties. Genetic information coding for when and where cellulose is produced. Cellulose is the most abundant carbohydrate polymer produced by living organisms and the major component of cotton fibers. Our team has analyzed the genetic information coding for the fiber enzyme that produces long chains of cellulose. By sequentially reducing the size of genetic information upstream of the gene for cellulose biosynthesis, we have determined essential regions that control the activity of the gene in fiber cells. Capitalizing on this information will increase the specificity of delivering novel transgenes that will enhance fiber properties. Determinants of cotton fiber number per seed. Fiber yield is usually expressed as the number of bales per acre, but yield is also determined, in part, by the number of fibers per seed. Although genetic and environmental effects are known, the physiology of seed development also plays a role in determining the number of fibers per seed. Two hormones produced by plants are essential for cotton fiber growth and development. Using a technique called microarray analysis, the activities of >21,000 genes were compared in young cottonseeds growing in the presence and absence of plant hormones. Identifying the network of gene activity required in young cotton seeds to produce more cotton fiber cells will facilitate molecular genetic improvement of fiber yield. A Specific Cooperative Agreement with University of New Orleans and a Reimbursable Agreement with the National Aeronautics and Space Administration terminated in January 2007. NP 302, Component: 2, Problem Statement: a, and NP 306, Component: 6, Problem Statement: c.
Impacts
(N/A)
Publications
- Kim, H.J., Kato, N., Kim, S., Triplett, B.A. 2008. Cu/Zn superoxide dismutases in developing cotton fibers. Planta. 228:281-292.
- Chen, Z., Scheffler, B.E., Dennis, E., Triplett, B.A., Zhang, T., Chen, X., Stelly, D., Rabinowicz, P., Town, C., Arioli, T., Brubaker, C., Cantrell, R., Lacape, J., Ulloa, M., Chee, P., Gingle, A.R., Haigler, C.H., Percy, R. G., Saha, S., Wilkins, T., Wright, R.I., Van Deynze, A., Zhu, Y., Yu, S., Guo, W., Abdurakhmonov, I., Katageri, I., Ur-Rahman, M., Zafar, Y., Yu, J., Kohel, R.J., Wendel, J., Paterson, A. 2007. Towards Sequencing Cotton (Gossypium) Genomes. Plant Physiology. 145:1303-1310.
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Progress 10/01/06 to 09/30/07
Outputs
Progress Report Objectives (from AD-416) Characterize the structure and function of genes and their associated promoters that are required for cotton fiber development. Approach (from AD-416) Conduct functional analyses of cotton fiber genes previously isolated by differential display and other methods; use rapid methods for evaluating the efficacy/strength of cotton promoters without the need to construct transgenic cotton plants; measure minimal sizes of cis elements that specify the temporal/spatial localization patterns and hormonal induction of cotton fiber gene expression; determine if promoter structures are different for selected genes in G. hirsutum, G. barbadense, and other Gossypium species; evaluate how long gene expression proceeds during fiber development and whether there are any very late genes expressed in cotton fiber. Significant Activities that Support Special Target Populations Molecular genetic comparison of cotton plants that differ in fiber strength: Although cotton fiber strength is genetically controlled, the genes involved in producing strong fiber have not been identified. Using a method called microarray analysis to compare simultaneously the activities of >21,000 cotton genes, two closely related types of cotton plants that differ in fiber strength were analyzed. Candidate genes from this study have been selected for additional analyses. Future work on this project will include a seasonal replication of the experiment to validate the current results, and conversion of the data into a resource that can be utilized to breed new varieties of cotton with enhanced fiber strength. Novel enzyme is localized in cotton fiber cell walls: -- The enzyme superoxide dismutase converts a reactive form of oxygen into the less toxic molecule, hydrogen peroxide. Using several innovative techniques to label proteins produced by model plants, we have demonstrated that the cell wall, the hard covering for each cell, contains a special form of superoxide dismutase. Potential functions of this protein include the control of fiber length and strength. Since the gene for the cell wall form of superoxide dismutase does not contain genetic information that normally controls the final destination of this enzyme, additional study of this gene is expected to reveal new mechanisms that specify how proteins are directed to the surface of plant cells. This line of genomic investigation is expected to contribute to new strategies for modifying cotton fiber structure and properties. Genetic information coding for when and where cellulose is produced: -- Cellulose is the most abundant carbohydrate polymer produced by living organisms and the major component of cotton fibers. Genetic information residing within each gene determines when, where, and how much of each protein gene product (enzyme) will be made by living cells. Our team has analyzed the genetic information coding for the fiber enzyme that produces the long chains of cellulose. By sequentially reducing the size of genetic information upstream of the gene for cellulose biosynthesis, we have determined essential regions that control the activity of the gene in fiber cells. Capitalizing this information will increase the specificity of delivering novel transgenes that will enhance fiber properties. This Agricultural Research Service (ARS) research project is also the in-house project of the following cooperative agreements involved in like research: National Aeronautics and Space Administration/6435-21440-003-01R and 6435-21440-003-02R; and University of New Orleans/6435-21440-003-03S. Technology Transfer Number of Active CRADAS and MTAS: 3 Number of Non-Peer Reviewed Presentations and Proceedings: 13 Number of Newspaper Articles,Presentations for NonScience Audiences: 2
Impacts
(N/A)
Publications
- Atlaf-Khan, M., Kim, H.J., Myers, G.O., Triplett, B.A. 2006. GhSEM-1 marker potentially associated with regeneration ability in cotton.. Journal of Crop Improvement. 16. p. 21-35.
- Triplett, B.A. 2006. Fibres. Encyclopedia of Seeds: Science, Technology and Uses. In Bewley, J.D., Black, M., Halmer, P. editors. The Encyclopedia of Seeds. Science, Technology and Uses. Oxford, UK.: Oxford University Press. pp. 1000.
- Yang, S., Cheung, F., Wei, N.E., Lee, J.J., Sze, S., Stelly, D.M., Thaxton, P., Triplett, B.A., Town, C.D., Chen, J. 2006. Accumulation of genome- specific transcripts, transciption factors and phytohormonal regulators during early stages of fiber cell development in allotetraploid cotton.. Plant Journal. 47. p. 761-775.
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