Abstract:

【Objective】 This study aims to compare the transcript profiles between the cotton fuzzless mutant and its isogenic line in order to identify the genes which are involved in cotton fiber development. 【Method】 Scanning electron microscope (SEM) was used to observe the differential fiber developmental patterns between the fuzzless mutant GZnn and its isogenic line TM-1, and differential display PCR was employed to identify the differentially expressed genes. These resulting fragments were sequenced and analyzed by BLASTx. 【Result】 Using SEM to examine the cellular events of fiber cell development in the mutant GZnn, it was found that not only the process of fiber cell formation and elongation delayed, but also the fiber number reduced in the mutant in comparison with TM-1. By using differential display RT-PCR, 12 differentially expressed cDNA fragments were obtained, among which DS3 showed high degree of similarity to myb family transcription factors and was expressed exclusively in ovule before anthesis (-3-0 DPA) in the mutant, but not in that of TM-1. Therefore, DS3 might be a negative regulator during fiber initiation. 【Conclusion】A large number of genes were expressed specifically during cotton fiber initiation and development. Further investigations on the genes which play key roles during this process are of help to understand the molecular mechanisms underlying the differentiation and development of cotton fibers, and this will contribute to cotton genetic improvement.

Key words: cotton (Gossypium hirsutum L.), fuzzless mutant, SEM, fiber cell initiation, mRNA differential display, RT-PCR