Characterisation of rice anther proteins expressed at the young microspore stage

In combination with two-dimensional polyacrylamide gel electrophoresis (2-DE) protein mapping and mass spectrometry analysis, the pattern of gene expression in specific tissues at a specific stage can be displayed and characterised. We used this approach for rice (Oryza sativa L. cultivar Doongara) to display and assign identity to proteins in the anthers at the young microspore stage. Over 4000 anther proteins in the pI range of 4-11 and molecular mass range of 6-122 kDa were reproducibly resolved after silver staining, representing about 10% of the estimated total genomic output of rice. Two hundred and seventy-three protein spots have been extracted either from polyninylidene diffluoride membrane blots or from colloidal Coomassie blue stained 2-DE gels and analysed by N-terminal sequencing, Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MS) analysis or tandem MS sequencing. This enabled identification of 53 anther protein spots representing 43 different proteins. Using the publicly available rice expressed sequence tag (EST) database at the National Centre for Biotechnology Information, a further 37 protein spots were matched to ESTs. After BLAST searching with these ESTs, we were able to predict the identity of 22 of these protein spots. Proteome reference maps of rice anthers have been constructed according to the SWISS-2DPAGE standards and are available for public access at http://semele.anu.edu.au/2d/2d.html.