| Tung trees are original from China and they are famous for tung oil in the world as an oilplant. Tung oils are widely used in industry as a good kind of dry oils.In the paper, the protein expression profiles were successfully constructed during thedevelopmental periods by the method of traditional and classical research on proteomics. Itcould help to explain the accumulation process of tung oil in tung seeds from the proteins level.The results indicated that there existed a close relationship between the oils accumulation andthe proteins expression especially for which related to fatty acids metabolism. The oilaccumulation was co-determined by a series of proteins expression and the development of oilbody visualization shows this process. In order to explain the oil biosynthesis from the proteinlevel, many research works were held on and the main results obtianed as follows:(1) TCA-acetone combined with phenol method was the most suitable for the protensextraction from tung seeds. This method can effective clear away the nucleic acids, sugars andphenols, thus the contribution of sample arrived at8.1μg/μL. It also found that it had a goodcapability in extracting high and low mass protiens after SDS-PAGE. In addition to, the resultsof2-DE pointed that the sample which prepared by TCA-acetone combined with phenol had aclear background and a good resolution.(2) It successfully constructed a2-DE platform for tung seeds with a high stability andrepeatability. Some factors can effects the2-DE process such as lysis solution, loading yield ofproteins, IEF and SDS-PAGE were compared. It indicated that the protein samples whichprepared by TCA-acetone combined with phenol were dissolved by7M urea,2M thiourea,4%CHAPS,65mM DTT and2%IPG buffer, then after IEF for70000Vh with the loadingyield of700μg, we could obtain a good2-DE patterns for tung tree seeds proteome.(3) It indicated that after flowering130d~160d was the key periods for the oilsaccumulation. This period can grouped into three stages by the change of oil content and thecolor change of seed coat. (4) A total of144proteins were determined as differential expression proteins, and76proteins were successfully identified by MALDI-TOF/MS/MS. They were classified into11classes including energy metabolism (25%), fatty acid metabolism (15.79%), defense-related(14.47%), protease (11.84%) and so on.(5) Energy metabolism (TAC cycle and glycolytic pathway) was the main change duringdevelopment besides fatty acids metabolism. The expression change of S29(malatedehydrogenase) and S62(3-phosphoglycerate kinase) during three stages indicated that TACcycle and glycolysis would be stronger along with development. The expression change ofmost proteins which related to fatty acids metabolism was similar to the speed of oilsaccumulation in seeds. It was parabola style, the highest value existed in S2. This result canhelpful for explain the oil accumulation from protein level. RT-PCR results indicated that theprotein which related to energy metabolism and fatty acids metabolism have a similar changeprocess with the MS results, it stands for the MS results owned a high reliability. We also canobtain a similar result as (5) and (6) by RT-PCR.(8) The oil bodies owned different cytological characteristics in the differentdevelopmental stages. According to this, the process of oil body development can divide intothree stages as the earlier stages, the middle and the last stages of development. There existed anegative correlation in the number of oil bodies in the endosperm cells and the oil content;existed a positive correlation in the diameter of oil bodies in cells and the oil content in tungseeds. The oil bodies development process owned a close relationship with the oilaccumulation in tun seeds and the proteins expression change which related to fatty acidsmetabolism. |
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