Recently, proteome analysis is becoming a powerful tool for the functional characterization of plants. Due to the availability of vast nucleotide sequence information and based on the progress achieved in sensitive and rapid protein identification by mass spectrometry, proteome approaches open up now perspectives to analyze the complex functions of model crop species at different level. In this study, we have N-terminal sequencing data for the 100 embryo and 53 seed proteins of rice separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) were collected and systematically organized for a protein sequence data-file. An attempt was made to link the embryo proteins of rice to DNA sequences for understanding their functions. One hundred proteins of the 700 spots were detected in the embryo using 2-DE gels whereas we used micro sequenced. Of these, 28% of the embryo proteins were matched to DNA sequences with known functions, but 72% of the proteins were identified to be unknown functions as previously reported by Woo et al.,. In addition, twenty-four spots of protein with 100% of homology and nine with over 80% were matched to ESTs (expressed sequence tags) after expanding the amino acid sequences of the protein spots by Database searches using the available EST databases of rice at the NCBI (http://www/ncbi.nlm.nih.gov/) and DDBJ (http://www.ddbj.nig.ac.jp/). Also, a total of 53 proteins out of 700 protein spots separated on the 2-DE gels were analyzed by the peptide mass fingerprinting method (MALDI-TOF/MS). High-quality mass spectra suitable for peptide mass fingerprinting were obtained from 41 spots. Using the ESI-Q-TOF/MS, however, we were able to identify 53 seed proteins of rice, including 12 proteins not registered in database. The rapid expansion of DNA sequence databases to the utilization of EST now provides the whole or partial gene sequences of model organisms, and the recent advances in protein micro-characterization by mass spectrometry allow the possibility of linking these DNA sequences to the proteins in functional complexes. Proteome Database of rice is updated, and is available on the World Wide Web at http://gene64.rda.affrc.go. This work shows that the proteome analysis could be a useful strategy to link the sequence information to the functional genomics.

Research Institute (HARI), NTCS, RDA, in 2004. This cultivar has a short grain shape and about 123 days growth duration from trans-planting to harvesting under the reclaimed saline area of the south-western and the mid-western coastal plain and Honam plai