Genetic and Functional Genomic Analysis of Early Events in Cotton Fiber Development
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 lint. Initiation of an epidermal cell into fiber requires a change in cell fate, which is a fundamental biological process involving genetic, physiological and developmental "switches". Genetic mutations, polyploidy, pollination/fertilization, and hormonal regulation can affect the number of cells developing into fibers or alter fiber cell properties (fuzz vs. lint). However, it is unclear how these factors control gene expression changes that orchestrate the pattern and tempo in early stages of fiber development.
We are employing genetic and functional genomic approaches to investigate molecular events concomitant with fiber cell initiation. We are developing ESTs from immature ovules and fiber cell initials (-3 to 3 DPA) and studying gene expression changes in the isogenic naked seed mutants in G. hirsutum L. and G. barbadense L. backgrounds that uniquely enable genetic dissection of transcriptome alteration during fiber cell initiation. Moreover, we are investigating the effects of pollination, fertilization, and phytohormones on fiber cell initiation.
A combination of genetic, developmental, and physiological studies will provide an extraordinary opportunity to reveal gene expression patterns associated with the fundamental process of fiber cell initiation and development. 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. The functions of candidate genes will be tested using powerful Arabidopsis genetics, which will benefit from tools and mounting genomic resources developed in the model system. In addition, new genetic markers will be developed from ESTs especially those differentially expressed in mutant isolines for cotton breeding.
This project is funded by the National Science Foundation and is a joint effort among five participating laboratories: the Chen lab, the Stelly lab, the Sze lab, and the Thaxton lab at the Texas A&M University and the Triplett lab at the USDA-ARS, New Orleans, LA.
