Quantitative Proteomics Analysis Of Regenerated Secondary Vascular System In Populus Tomentosa

The forest is an important material for a set of ecological economic and social benefits in the world. However,the lack of the forest and material resources in China. The quantity and quality of the timber can not meet the social diversity. the forest area and wood production is an important task. The afforestation area is limited. How to improve the quality of wood is an important way.Wood formation is a complex process involving many genes expressed and regulared coordinately in the different developmental stages of secondary vascular system(SVS).Proteins directly involve in physiological and biochemical reactions of plant than mRNAs, and to reflect function and expression of genen in organism.Thus, quantitative proteome profiling of SVS development may reveal important insights into the mechanisms of wood formation.Using the regeneration system of SVS previously established in Populus tomentosa by our laboratory. Samples were subsequently collected by scraping regenerating tissues from the whole surfaces of the trunks at the 6, 8, 10, 12, 14, 16, 18 and 20 days, extraction, trypsin digestion and labeled with an 8-plex isobaric tags for relative and absolute quantitation(iTRAQ) of proteins were performed,and analyzed by strong-cation-exchange(SCX) and reverse phase(RP) a multidimensional chromatography system in conjunction with 4800 MALDI-TOF/TOF MS. 2019 distinct proteins were identified with 95% confidence, 401 of which quantitative proteins were identified with unused ≥1.3 and peptides(95%) ≥ 1, and 225 of which quantitative proteins were identified with unused ≥1.3 and peptides(95%) ≥ 2. The function of all the 2019 and 225 proteins were determined by classifying with gene ontology in WEGO. The hydrolytic enzyme protein kinases(MAPK) were categorized functional proteins as the first type.The structure and composition of wood have impacted by plastic esterase, galactosyl transferase enzyme and the class of cell wall synthesis enzymes in the secondary vascular regeneration process. Regulatory proteins as the second type. transcriptive regulation and signal transduction direct and indirect effects on SVS.the proteins expression profiles of SVS were established.The regeneration of the SVS in debarked Populus tomentosa stems started with the callus produced from the left immature xylem, then the callus differentiated into xylem and phloem.The process involvied in cell division, cambium formation and differentiation, which is controlled by complex signal transduction and transcriptional regulation. 86 relative quantitative distinct proteins related to cambium, 65 related to xylem defferentiation, 39 related to cell wall synthesis, 15 related to signal transduction and 12 relative quantitative distinct proteins related to transcriptive regulation. In the identification of proteins and found that some of the known functional protein. PtCLE44 relate to cambium formation. PtCAD、PtCOMT and PtPAL relate to lignin biosynthesis.and in the different developmental stages of secondary vascular system relate to regulate during xylem formation.MYB is transcriptive factor, MYB48 and MYB4.1 play a negative regulation during xylem formation. The results show that strong-cation-exchange(SCX) and reverse phase(RP) a multidimensional chromatography system in conjunction with 4800 MALDI-TOF/TOF and relative and absolute quantitation(iTRAQ) of proteins Methods of Feasibility.we identified 17 unknown function proteins for wood formation using quantitative proteomics, PtGNOM, PtTCTP and PtSLP may relate to cambium formation, PtADL and PtVEP might relate to xylem pattern formation, Pt MYB158 may play a negative regulation during xylem formation, PtCYP75B1, PtP78 RF and PtMIPS may relate to auxin responding factors, PtCHIA may relate to ethylene signaling associated proteins, PtCAT may invove in programmed cell death, In addition, 18243214 protein belongs to GRAS transcription factor family, 18250652 protein belongs to F-box transcription factor family and PtHB-1(18231790) protein belongs to PHOX2/ARIX transcription factor family. Three transcription factors may relate to cambium formation. On the other hand, 18241152 and 18242281 proteins are calmodulins binding and PtCPDK is calcineurin, which may of participate in SVS regeneration.Based on the result, we proposed a model for SVS regeneration in Populus tomentosa, our hypotheration model describes the molecular features of SVS regeneration after bark girdling in Populus tomentosa.Pre-programed expressions of these diverse groups of the functional protein are consistent with the developing process of SVS, and it can indicate that dynamic changes expression of special protein during the progress of regeneration.These proteins can be used as candidates protein for studying the regulation of wood formation, and for protein resources for modification of wood properties using genetic engineering.