| Wood formation is a complex process involving many genes expressed coordinately in the different developmental stages of secondary vascular system (SVS). Among the expressed products of genes, proteins play the direct role in embodying the characters and functions of SVS than mRNAs do. Therefore, the study of the dynamic process of the protein profiles is helpful to find the key genes and elucidate their functions during the wood formation process.A regeneration system of SVS previously established in Populus tomentosa by our laboratory was used to investigate proteomic profiles during this process. A serially sampling scheme and a multidimensional chromatography system (Isoelectric Focusing Chromatography + NPS Reverse Phase HPLC) followed by MALDI-TOF MS were combined to analyze the changes of proteomes. Three thousands two hundred and ninety two protein fractions were found expressed differently during this process starting from callus formation, initiation of cambium, and xylem and phloem differentiation, of which 724 were non-redundant after identification. These included 28 (3.9%) cell cycling and cell division associated proteins, 16 (2.2%) cytoskeleton related proteins, 48 (6.6%) proteins in signal transduction, 33 (4.6%) transcription factors and related proteins, 6 (0.8%) photosynthesis associated proteins, 109 (15.1%) cell wall synthesis and other metabolic proteins, 205 (28.3%) proteins involved in other biological process, and 279 (38.5%) proteins which were assigned as "function unknown" by database query. Interestingly, some of these "function unknown" proteins specifically expressed during the early stage of regeneration, suggesting they may involve in cambial initiation and differentiation. Since fewer proteins involved in the development of secondary vascular systems in woody plants exist in the current... |
PDF Full Text Request