Activation of Arabidopsis seed hair development by cotton fiber-related genes

This experiment was designed to investigate the molecular basis of cotton fiber cell initiation. 32,000 ESTs were sequenced from Gossypium hirsutum L. TM-1 immature ovules (GH_TMO) and developed cotton oligonucleotide microarrays containing ~23,000 unigenes. Transcriptome analyses were performed to compare gene expression changes in laser capture microdissected fiber cell initials (or epidermis) and inner ovules. The gene expression profiles of the fiber cell initials were compared with those of the inner ovules in each developmental stage prior to, right at, and shortly after the initiation of fiber cells. Many genes in various molecular function or biological processes were over- or under-represented between fibers and non-fiber tissues in each developmental stage, suggesting temporal regulation of gene expression during early stages of fiber development. For gene expression studies using a large set cotton oligo-microarray, 4 developmental stages were chosen. To study differential expression during fiber initiation, ovules at -2 DPA, 0 DPA, and 2 DPA were used. One of the fiber elongation stage tissues (7 DPA) was included. In each developmental stage, epidermis was separated from inner ovules and subjected to the hybridization. In addition, epidermis and ovule comparisons were performed individually with 0 DPA as a control point for comparison.