Comparative Proteomics Of Cotton Fiber Initial And Elongation Process

Cotton is a Malvaceae Gossypium plant, it is native to subtropical. Cotton is the world’s most important cash crop, the main product is fiber. Cotton fibers by the differentiation of the epidermal cell of cotton ovule, the development of cotton fibers can be divided into four mutually overlapping stages:fiber initiation; fiber elongation stage (primary cell wall synthesis and deposition); secondary cell wall synthesis; maturity.The yield and quality of cotton fiber is determined by the number of differentiation ovule cell and the length of cotton fibers elongation, that is to say the yield and quality of cotton fiber is depends on the stage of initial differentiation and fast elongation. Protein is a direct participant in the organism’s physiological and biochemical activity,the research of proteomics can directly reflect the regulation of physiological and biochemical activities during the development of fiber.so the proteomics research about the stage of initial differentiation and fast elongation of cotton fiber can help us to understand the mechanism of ovule cell differentiation and fiber elongation. This research will help us to make cotton varieties improvements.In this experiment, cotton XuZhou142and its lint-less mutant (fl) was used as a research material to the proteomics research of fiber starting stage. This experiment analysis the compare proteomic of ovule under the period of-2dpa, Odpa and3dpa, identified94proteins, Based on GO functional annotation, these proteins were involved in glucose metabolic pathways; cytoskeleton-associated; cellular redox balance regulatory; transcription and translation regulatory and other functional types. They play different roles in the differentiation of ovule cells, they regulate the fiber cell differentiation and starting.Generally, the elongation of fiber lasts from Odpa to20dpa, three stages:3dpa and5dpa,8dpa and lOdpa,15dpa and20dpa, were chosen to conduct a comparative proteomics analysis of cotton fiber. Finally,274spots of proteins were identified, including:(1)carbohydrate metabolism related proteins;(2) cytoskeleton related proteins;(3) intracellular redox related proteins;(4) ATP and energy related proteins;(5) proteins related to folding, modification, transportation and metabolism;(6) transcriptional and translational regulatory proteins;(7) proteins involved in response to a stimulus;(8) Other functional proteins and unknown proteins. These proteins play different roles in the elongation of fiber: some such as regulate the expression of certain genes by transcription and translation, some regulate proteins activity and functional subcellular organelles by protein folding, modification and transportation, some promote the synthesis of cell wall structure (cellulose, pectin etc.) and cytoskeleton (microtubules, actin filaments etc.), which provide structural components for rapid cell elongation, and others influence carbohydrate metabolism and ATP synthesis which provide energy for fiber elongation and turgor pressure for cell elongation, in addition, H2O2signal and ethylene signal related proteins also can facilitate fiber elongation. Under the combined effect of all proteins, physiological and biological activities and morphological structure of cell are changed.Else, We detected mRNA expression level of16proteins during fiber elongation, and compared with protein expression level. As a whole, no significant correlation between them is found. But it is found that4proteins expressions are completely consistent with mRNA expressions by the observations of single protein, others are not wholly consistent or completely inconsistent. This situation can be caused by the regulation at translation or post-translation level.