Abstract: Three cotton fiber protein extraction methods were compared using Gossypium hirsutum, cv. Xuzhou 142. Two-dimensional polyacrylamide gel electrophoresis was used to exhibit the protein profile differences between two stages of cotton fiber cells developments. The two stages are cell elongating and synthesizing primary cell walls at 10 days postanthesis (DPA), and the secondary cell wall thickening at 25 DPA. PDQuest8.0 software was used to analysis the relative abundance of different proteins between 10 and 25 DPA cotton fibers. Fifteen of the proteins which had good quality and reproducibility were identified by MALDI-TOF-MS. Gene specific PCR primers were designed according to the interest proteins nucleotide sequences. Semiquantitative RT-PCR was used to detect the five different proteins. The results showed that, the phenol-methanol-ammonium acetate extraction of cotton fiber proteins was the best method among three methods with a extract higher amount of protein extracted and clean SDS-PAGE loading pattern. According to the NCBI database searching results, the differentially expressed proteins were F-box family proteins, actin, β-tubulin, F1-ATP synthase subunit beta, annexin, cytosolic phosphoglycerate kinase 1, cytosolic malate dehydrogenase, adenosylhomocysteinase, putative glutamine synthetase, ATPase subunit, profilin, copper/zinc superoxide dismutase and putative 4-coumarate coA ligase. These proteins are involved in a wide range of physiological processes, such as energy metabolism, carbohydrate metabolism, cell cycle control and development.

Key words: Cotton fiber, Secondary wall, Proteome, MALDI-TOF-MS