Cotton represents nearly half of the world's natural fiber consumption. Each cotton fiber is a differentiated single epidermal cell of the ovule. Approximately half a million fibers are produced per cotton boll, some forming "fuzz" and some forming spinnable fibers. The process of turning an epidermal cell into a fiber cell requires a change in cell fate, a fundamental biological process involving genetic, physiological, and developmental "switches". Genetic mutations, genotypes, pollination/fertilization, and hormonal regulation can affect the number of cells developing into fibers or alter fiber cell properties. However, it is unclear how these factors control gene expression changes that orchestrate the pattern and tempo in early stages of fiber development.
Genetic and functional genomic approaches will be employed to investigate molecular events concomitant with fiber cell initiation. Changes in gene expression in immature ovules of isogenic naked seed mutants will be compared with expression profiles in pollinated and un-pollinated ovules and ovules treated with phytohormones. Both specific and common sets of candidate genes will be identified in a variety of genetic, developmental, and physiological conditions leading to fiber cell initiation. Furthermore, hypotheses concerning the roles of candidate genes in fiber cell initiation will be rigorously tested using the isogenic mutants and powerful Arabidopsis genetics.
Broader Impacts This interdisciplinary project will have broad and direct impacts on research, education, and the scientific community by creating genomic resources for public use and rendering their results directly applicable to the improvement and sustainability of the world's leading textile fiber crop. Genetic and genomic resources such as naked seed mutants, 20,000 expressed sequence tags (ESTs), molecular markers and oligo-gene microarrays will be released to the public domain as soon as they are confirmed and applied synergistically to train undergraduate and graduate students and postdocs with a special emphasis on under-represented groups. Data dissemination will include timely release of ESTs to GenBank and gene expression profiles to microarray data repositories such as GEO. An integrated plan involving graduate students and postdocs will be developed for early exposure of students and science teachers in middle schools to biotechnology and genomics. A 3-day educational workshop will be developed to promote public acceptance of plant biotechnology, as well as to train students and science teachers using hands-on experiments, laboratory tours, and field trips.
