Poster: Reproductive development
Abs #
351: Characterization of the Proteome of Pine Pollen Tubes: Towards Our Understanding of the Mechanism of Pollen Tube Development in Pines
Proteins that are differentially expressed in pollen tubes may play a significant role in pollen tube development. To reveal the identity of these proteins, comparative 2D gel electrophoresis was done using Pinus strobus proteins extracted from ungerminated pollen and 2-day old pollen tubes. Duplicate silver-stained 2D gels from both samples were scanned and analyzed. The results show that 645 and 652 protein spots in the pI range of 4.6 to 7.9 and Mr range of 14 to 172 kDa were clearly resolved from ungerminated pollen and pollen tube, respectively. 36 protein spots in ungerminated pollen were not found in pollen tubes, while 43 protein spots in pollen tubes were not found in ungerminated pollen. As for the protein spots with increased intensity (at least 5-fold), ungerminated pollen and pollen tube have 28 and 13 of these, respectively. To establish the identity of the differentially expressed pollen tube proteins, 23 protein spots were chosen and sequenced through Electrospray Ionization coupled with a Quadrupole Time-of-Flight Mass Spectrometry. Partial amino acid sequences were used to search various publicly available databases. Identification of all but 2 protein spots was successful based on similarity of sequences with previously characterized proteins from other species. In pine pollen tubes, several differentially expressed proteins are involved in metabolism (aldolase, dehydrogenase and enolase), signaling (calmodulin, calreticulin, and chaperonin), and defense response (reductase and peroxidase). The temporal and spatial expression patterns of these proteins are currently being investigated. This study shows that pollen tube development involves the expression of a unique set of proteins different from those expressed in the mature pollen.
