The Transcriptomic And Proteomic Studies In Embryogenesis Of Brassica Campestris L

Embryogenesis of higher plants is outset of sporophytic generation and is a crucial developmental period of life cycle. After fertilization, the zygote of dicotyledonous plants divides and develops subsequently into a globular embryo, continues with a heart-stage, a torpedo-stage, and mature embryo. The process from the fertilized egg to a mature embryo is called embryo development. The embryonic development of higher plants consist of series of complicated physiological and biochemical processes, including fertilization, asymmetric division of the zygote, the establishment of embryo plan and the accumulation of seed storage oils and proteins. Obvious fluctuation was showed in a series of biological macrdmolecules (DNA, RNA, proteins, etc.) during embryonic development of higher plants, especially in gene and protein expression. Many plants’genome has been sequenced completely, and transcriptome and proteome of embryonic development of many plants also extensively studied. However, transcriptome and proteome were not give enough study during embryogenesis of Brassica campestris. During the development of. Rape is an important oil and vegetable crop. Embryo of Brassica campestris is the most important organ producing oil and storage protein. It is very significant for improving the future quality of rapeseed to research transcriptome and proteome during embryonic development of Brassica campestris. This study contained mainly two parts:First, we screened differentially expressed transcripts during embryonic development of Brassica campestris using cDNA-AFLP, and selected216transcript-derived fragments (TDFs) for cloning and sequencing. Second, we screened differentially expressed proteins during embryonic development of Brassica campestris using two-dimensional electrophoresis, and identified protein by time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS). The results are as follows:1. Gene expression of embryogenesis of Brassia campestris L. is analyzed using cDNA-AFLPs technique. The whole embryogenesis was divided into six embryonic stages. In total,4267bands were obtained from embryogenesis of B. campestris L. A total of200TDFs, differentially expressed in six stages of embryogenesis, were selected for sequencing. By searching in BLASTN and BLASTX, most of185TDFs were homologous to Arabidopsis thaliana and Brassica napus sequences. As a result,162TDFs are matched with genes encoding either known or putative proteins in higher plants, and23TDFs are homologous to unknown genes. Besides, a selected subset of differentially expressed TDFs is confirmed by RT-PCR, and relative transcript abundance of TDFs was shown. Some embryo-specific genes are expressed in embryogenesis of B. campestris. Expression profiles of many TDFs show similarity to those of the relevant Arabidopsis genes. The potential roles of these genes in embryo development are discussed.2. To gain insights to the protein dynamics over different stages of embryogenesis in oil plant, a proteomic study on embryo development of Brassica campestris L. was carried out. The embryo proteins respectively at the globular embryo stage, heart stage, torpedo stage, bended-cotyledon stage and C-shaped mature embryo, were analyzed using two-dimensional gel electrophoresis. The identities of214spots with altered expression were determined by matrix-assisted laser desorption ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS). These proteins were classified into16groups according to their function, including primary metabolism, energy, transcription, Protein synthesis, protein processing/destination, transporter, cell structure, signal transduction, defense, secondary metabolism, transposon, DNA repair, storage, oxidation/detoxification, unclear classification and unknown. An unexpected result shows that protein processing/destination-related proteins take a large group, highlighting importance of protein renewal in embryogenesis of Brassica campestris L. Our results reveal different dynamic characters from that of whole seed development and provide new insight to the complex process of embryo development in plant.